1. food and drink
2. desserts and baking

UNIT 1
Lesson 1 Exercises
1. Possible answer: Chemistry containers are
made of glass because substances in a glass
container are visible and glass containers are
relatively easy to clean and reuse. Tempered
glass containers can be heated over flames
without shattering.
2. Possible answer: Appropriate clothing provides
protection, and has no loose or dangling parts
to interfere with safe lab procedures. While
in the lab, tie back long hair and wear safety
goggles, long pants or skirts, and shoes with
closed toes. Remove any dangling jewelry.
3. Possible answers (any 3):
• Know the location of safety equipment.
• Read lab instructions carefully.
• Check to be sure that you are using the right
chemicals and equipment.
• Follow directions from the teacher.
• Discuss the steps of the procedure with other
members of the group and assign tasks.
4. Possible answer: Immediately report the spill to
the teacher and follow instructions for cleaning
it up. If you come into contact with any
chemicals, rinse the affected area with water for
at least 15 minutes.
5. Possible answers (any 3):
• Put all equipment in its proper place.
• Clean your work area.
• Make sure all bottles and containers holding
chemicals are closed and stored properly.
• Safely dispose of used chemicals as indicated
by the teacher.
• Wash your hands.
6. A fire blanket is used to extinguish flames by
smothering a fire and depriving it of oxygen.
7. A hood keeps gases and fumes from entering
the laboratory by carrying them to a filter or by
venting them to the outdoors.
8. Chemists use clamps and ring stands to keep
glassware from toppling over and breaking
or spilling.
Living By Chemistry Solutions Manual
Lesson 2 Exercises
1. Alchemists developed some of the first
laboratory tools and chemistry techniques.
They classified substances into categories
and experimented with mixing and heating
different substances to create something new.
2. Chemistry is the study of what substances are
made of, how they behave, and how they can be
transformed. It is the study of matter and how
matter changes.
3. Time periods when alchemy was practiced:
China (early c.e.), India (b.c.e. to Middle
Ages), Middle East (early c.e. to recent), Greece
(late b.c.e. to early c.e.), Spain (Middle Ages),
England (Middle Ages), Egypt (b.c.e.).
A good answer will include
• goals of alchemists in their particular region
(which substances they were attempting to
transform or obtain)
• contributions that alchemists in the region
made to science
• a list of trustworthy sources for the
information given in the answer
4. Possible answer: Sodium hydroxide, or lye, is a
strong base used in manufacturing paper, soaps
and detergents, and in other industrial chemical
processes. In the home, sodium hydroxide is a
component of many drain cleaners.
Because it is a strong base, and therefore a very
reactive substance, sodium hydroxide is an
important industrial chemical used in many
chemical manufacturing processes. It tends to
break down organic materials, such as hair and
grease, which makes it useful as a drain cleaner.
5. Possible answer (any 10 examples total):
• Changes that involve chemistry involve
an alteration in the appearance of matter.
Examples include metal rusting, cookies
baking, ice cubes forming, wood burning,
water boiling, and sugar dissolving. Both
physical changes (such as changes of state)
and chemical changes (such as objects
burning or rusting) involve chemistry.
• Changes that do not involve chemistry only
involve matter moving to a different location.
Examples include the sun going down, objects
falling, hands moving on a clock, going for a
walk, throwing a ball, and riding a bicycle.
Unit 1 Alchemy
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Lesson 3 Exercises
1. Mass is the amount of material in an object.
Volume is the amount of space that the object
takes up.
2. Possible answer: A bicycle has mass because
when you lift it you can feel its weight. You
could further prove this by placing the bicycle
on a scale. A bicycle has volume because you can
see that it fills space that cannot be occupied by
anything else. You could further prove this by
lowering a bicycle into a bathtub and watching
the water level rise. Since it has mass and
volume, the bicycle is matter.
2. Possible answer: Not necessarily. Two objects
with the same volume can have very different
masses. For example, a cube of iron has much
more mass than a cube of wood that has the
same volume.
3. Yes, the volume of an object is the amount of
space it fills. You can usually see how much
space an object fills, and estimate its volume
based on its dimensions. However, for objects
that have an irregular shape, are very thin,
or have a surface with lots of holes or pits,
determining the volume of the object by sight
may be difficult.
3. Possible answer: If you use a balance to find
the mass of an empty balloon, then inflate the
balloon with air and tie off its end, you will see
that its mass has increased when you put it back
on the balance. The air inside the balloon must
have mass. Because the volume of the balloon
increases when the balloon is inflated with air,
the air inside the balloon also has volume. Since
the air inside the balloon has mass and volume,
it is matter.
4. No, the mass of an object does not depend only
on its shape and size, so you cannot predict an
object’s mass simply by looking at the object.
An incorrect answer is that the mass of a
known object, such as a piece of metal, can
be predicted by looking at its size. In this
case, knowledge about density is being used
in addition to visual information, or the
assumption is made that an object is made of a
certain material just by looking.
4. Possible answer: The Sun is matter because it
has mass and volume. Sunlight is not matter
because it does not have mass or volume. It is a
form of energy that can be detected visually and
that makes your skin feel warm.
5. Yes, the mass of the rubber band is the same
because only the shape of the rubber band
changes, not the amount of matter in it.
5. Possible answer (any 10 of each):
• Examples of things that are matter: a car, a
tree, a person, a cat, a brick, a desk, a pen,
water, a glass, a window, a rock, and the Sun.
Each of these objects has mass and volume.
• Examples of things that are not matter: light,
sound, movement, gravity, music, heat, time,
cell phone signals, feelings, energy, radio
waves, thoughts, memories, and forces. These
things do not have mass or volume. They are
forms of energy or are intangible.
6. Possible answers (any 5): sound, wind, rolling,
falling, running, flying, explosion, rain
Lesson 4 Exercises
1. Possible answer: To determine the measure
of a solid object, measure its dimensions and
calculate the volume using a geometric formula
or, if it does not float or dissolve, measure the
amount of liquid that it displaces when it
is submerged.
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6. a. Volume is the measure of the amount of
space the piece of clay occupies. Changing
its shape does not change the amount of
space it occupies.
b. No, the mass of the clay does not change,
because you did not add or subtract any
matter from the clay, and mass is a measure
of the amount of matter.
7. Possible answers:
a. Pour the pancake mix into a graduated
cylinder or a measuring cup and read
the markings.
b. Use a measuring spoon or measuring cup.
c. Measure the dimensions of the box and
multiply the length by the width by the height.
d. Measure the thickness and radius of the penny
and calculate its volume using the formula
for the volume of a cylinder or measure
the amount of liquid it displaces when it
is submerged.
e. Pour the lemonade into a graduated cylinder
or a measuring cup and read the markings.
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© 2012 W. H. Freeman and Company/BFW
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The key concept of the question is that the
volume of fluids can be measured directly,
while the volume of a solid material can be best
measured by its dimensions or displacement.
8. Possible answer:
The exercise specifies that the cubes are exactly
the same material, so they should have the
same mass since they are the same volume. This
eliminates the possibility that the substance is
wood, plastic, or some other substance where
the density may vary. The only remaining
possibility is measurement error due to human
error or limits to the instrument’s precision.
Lesson 5 Exercises
1. Possible answer: Density is the mass of an
object divided by its volume.
The drawing should clearly show that the
masses of the two objects are the same. This can
be done using a balance, as shown above, or by
using labels. For example, a large cube could
be labeled “polystyrene foam” and a small cube
labeled “wood.”
9. Possible answer:
2. If the density of the penny (its mass divided by
its volume) is not equal to the density of gold
(19.3 g/cm3), then the penny is not made of
solid gold.
3. The density of aluminum is less than the
density of gold. More matter is present in a
given volume of gold than in the same volume
of aluminum.
4. C
The drawing should clearly show that the
masses of the two objects are different. This can
be done using a balance, as shown above, or by
using labels. For example, two beakers could
be shown, one labeled “sand” and the second
labeled “water.”
10. a. 150 mL
b. Because the rock is completely submerged
in the water, the volume of the rock is equal
to the volume of water that it displaces. The
displaced volume is equal to the change in
the water level: 200 mL − 150 mL = 50 mL.
One mL is equal to one c​m3​ ​, so the volume of
the rock is 50 mL, or 50 cm3.
11.Possible answer: The balance or scale that
was used to measure the two different cubes
may not be able to measure accurately to a
hundredth of a gram. The two cubes could
have exactly the same mass because the
measurement error is greater than 0.03 g.
Living By Chemistry Solutions Manual
5. Possible answer: The object that has a density
of 2.7 g/cm3 has a larger volume than the object
with a density of 8.4 g/cm3. The two objects
have the same mass, but the mass is packed into
a smaller space in the denser object.
m 
6. D   __
V
252 g
________
 ​ 
  ​ 
30.0 c​m3​ ​
  8.40 g/cm3
The metal could be brass because the table
shows that the density of brass is 8.4 g/cm3.
Brass is a possible identification based on the
table but note that density alone is not adequate
to identify a material because other materials
could have the same density.
m 
7. a. D   __
V
18.5 g
________
      ​ 6.45 c​m 
3​  ​​ 
       2.87 g/cm3
b. 6 • 18.5 g  111 g
6 • 6.45 cm3  38.7 cm3
Unit 1 Alchemy
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m 
D   __
V
111 g
________
       ​ 38.7 c​m 
3​  ​​ 
       2.87 g/cm3
c. The density of six glass marbles is the same
as the density of one glass marble because
density is an intensive property of the glass in
the marbles.
Section I Review Questions
1. Possible answer: Determine the volume of
a powdered solid or of a liquid by pouring
the substance into a graduated cylinder or
beaker and reading the markings on the side.
Determine the volume of a rock by submerging
the rock in a graduated cylinder partially filled
with water and then reading how much the
water level changes.
2. Possible answer: Matter is anything that has
mass and takes up space.
3. Density is no help in determining which object
will displace more water. A large object will
displace more water than a small object no
matter how dense the two objects are.
m 
4. D    __
V
2.6 g
D(one penny)  ________
​ 
  ​ 
0.36 c​m3​ ​
       7.2 g/cm3
5.2 g
D(two pennies)  ​ ________
  ​ 
0.72 c​m3​ ​
        7.2 g/cm3
The density of one penny is the same as the
density of two pennies.
5.Possible answer: The density is the same
because the pebble is made of the same material
as the boulder. Although the pebble has a
smaller mass, it also has a smaller volume, so
the density can be the same.
6. m   DV
  10.5 g/cm3 • 238.1 cm3
Lesson 6 Exercises
1. Elements are the building materials of all
matter. A compound is matter that is made up
of two or more elements combined in a specific
ratio. An element cannot be broken down into
simpler substances by chemical means, but a
compound can be broken down into elements.
2. The physical form of a substance is its phase:
gas, liquid, or solid. An aqueous solution is
another physical form.
3. The chemical formula for sodium nitrate,
NaNO3, indicates that it has three elements:
sodium, Na, nitrogen, N, and oxygen, O.
4. NaOH(s) is the symbol for solid sodium
hydroxide. NaOH(aq) indicates that the sodium
hydroxide is dissolved in water.
5. The chemical formula for cubic zirconia is
ZiO2. The chemical formula for diamond is C.
The stone cannot be a diamond because it has a
different chemical formula than a diamond.
6. These steps present possible dangers:
• Step 2: Wear goggles and gloves to protect
your eyes and skin from the nitric acid. Do
your work under the hood to avoid breathing
harmful gases. Pour the liquid slowly to avoid
spills. In case of skin contact, wash your skin
and notify the teacher.
• Step 3: Wear goggles and gloves to protect
your eyes and skin from the sodium
hydroxide. Pour the liquid slowly to avoid
spills. In case of skin contact, wash your skin
and notify the teacher.
• Step 4: Avoid touching the beaker or the hot
plate directly. Wear gloves to protect your skin.
Stir the liquid carefully to avoid splashing hot
liquid. In case of skin contact, wash your skin
and notify the teacher.
• S tep 5: Avoid touching the beaker or the hot
plate. Wear gloves to protect your skin. Be
careful transporting the beaker to the lab table.
In case of skin contact, or a dropped beaker,
notify the teacher, wash your skin, and make
sure to sweep up all the pieces of broken glass.
  2500 g
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• Step 8: Wear goggles and gloves to protect
your eyes and skin from the sulfuric acid. Pour
the liquid slowly and stir carefully to avoid
spills. In case of skin contact, wash your skin
and notify the teacher.
Lesson 7 Exercises
1. Possible answer: A chemical reaction is a change
leading to the final substance or substances
being different from the original substance
or substances. Some of the signs that a new
substance has formed include
• color changes
• formation of a new solid
• formation of a gas
• the release of energy as heat or light
• an increase or decrease in the mass of material
• a change in the texture of a material
2. Possible answer: The copper would always be
present throughout the series of reactions.
The copper could be in a different form after
each reaction. For example, the copper could
become part of a compound, then be dissolved
in water, and then extracted and returned to its
pure form.
3. Possible answer: A chemical reaction combined
the zinc with part of the dissolved copper
compound. The resulting zinc compound
was also dissolved in water. The zinc was still
present, but not as a pure element.
In fact, when the zinc was added, it formed a
colorless solution of zinc sulfate and the copper
came out of the solution as a precipitate.
4. Yes, the ingredients undergo a chemical
change. The cookies are a different color
and consistency from the cookie dough.
These changes are present even after the
cookies cool to room temperature.
As the cookies bake, the dough absorbs heat
energy, which causes a chemical change in the
ingredients of the dough. The composition of
the cookies is very different from the original
ingredients and from the dough.
Living By Chemistry Solutions Manual
5. a. The baking soda is a solid, the vinegar is a
liquid, the clear colorless liquid is a liquid,
and the CO2is a gas.
b. Yes, the production of carbon dioxide gas
is evidence that a chemical change has
occurred after the original liquid and solid
substances were mixed. The solution also
becomes colder and the odor of the vinegar
disappears—other indications of the
chemical change.
c. Before the change, the sodium is in the solid
baking soda. After the change, the sodium
must be in the clear colorless liquid.
In fact, when baking soda is mixed with vinegar,
the result is sodium acetate, CH3COONa,
dissolved in water.
6. Possible answer: Copper ore is crushed into
a powder and changed to a copper sulfate
solution by a chemical reaction. When an
electric current passes through the solution,
the copper metal comes out of the solution as
copper deposited on a metal plate.
Lesson 8 Exercises
1. Possible answer: The chemical names and
symbols indicate what compounds were
combined in each step. Because matter is
conserved, the products must contain the same
elements as the original compounds, which
enables you to make a reasonable guess about
the products. For example, when sulfuric acid
combines with copper oxide, it is likely that
copper sulfate and water are the products.
2. Possible answer: The law of conservation of
mass states that matter cannot be created or
destroyed in a chemical reaction.
3. A good lab report will contain
• a title (Lab: The Copper Cycle)
• a statement of purpose (Possible Answer: To
perform a series of chemical reactions that
begin and end with copper powder)
• a procedure (a summary of the steps followed
in the experiment)
• results (Check student observations to make
sure they noticed the changes that occurred
during each step of the copper cycle, including
color changes, formation of gas, formation of
precipitates, and dissolving of solid materials.)
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• a conclusion (The conclusion should include
a statement related to the conservation of
matter. Possible answer: Although the copper
seemed to disappear, it was still present in
the substances in the beaker during the entire
series of chemical reactions. This was proved
by recovering the copper at the end of the
series of reactions.)
4. Possible answer: The copper cycle experiment
shows that the copper is never lost and implies
that it is a component in other compounds
formed during the experiment.
Elements also cannot be broken down into more
fundamental building blocks. The copper cycle
experiment does not prove that copper cannot
be broken down into simpler building blocks.
But, the experiment does support the conclusion
that copper is an element based upon the
definition of element given in Lesson 6.
5. The solution would be yellow because the
combination of nickel, Ni, and hydrochloric
acid, HCl, can only produce a solution
containing compounds with nickel, hydrogen,
and chlorine. Nickel chloride, NiCl2, is a
possible product and forms a yellow solution.
Nickel sulfate, NiSO4, is not a possible product.
6. The zinc reacts with the sulfate part of the
copper sulfate to form an aqueous solution of
zinc sulfate. The precipitate is pure copper, so
the zinc and the sulfate must be present in the
dissolved compound.
7. Possible answers (any 2):
• Oxygen, carbon dioxide, water, and other
important resources can cycle through the
environment over and over again.
• Dangerous waste products that cannot break
down into safer substances will always be
present in the environment.
• The resources that are currently available on
the planet are the only resources that will
ever be available, unless a method of bringing
more material from outer space to Earth
is developed.
Lesson 9 Exercises
1. Three useful properties for sorting elements are
reactivity, formulas of their compounds, and
atomic mass.
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2. Carbon, C, is most similar to silicon, Si, because
both elements are located in the same column
of Mendeleyev’s periodic table of the elements.
Mendeleyev sorted the elements, placing
elements with similar properties in the same
column. Carbon is in the same column as
silicon, but not in the same column as nitrogen
and oxygen.
3. a. Possible answer:
Si
P
Ge
S
Se
Sn
Sb
b. Possible answers (any 2 for each column):
• Column 1: Combines with chlorine in
a 1:4 ratio, solid at room temperature,
nonreactive.
• Column 2: Combines with chlorine in a
1:3 or a 1:5 ratio, reactive, brittle, solid at
room temperature.
• Column 3: Combines with chlorine
in a 1:2 ratio, reactive, brittle, solid at
room temperature.
Multiple correct answers are possible. The
answer above uses the same logic as was
followed in Lesson 9. The columns are
organized using the ratios of the atoms when
combined with chlorine. The rows are organized
using the atomic mass of the elements.
• silicon: average atomic mass 28.09, gray, solid,
metalloid, nonreactive, forms compound SiCl4
• germanium: average atomic mass 72.61,
gray, solid, metalloid, nonreactive, forms
compound GeCl4
• tin: average atomic mass 118.7, silverywhite, solid, metal, nonreactive, forms
compound SnCl4
• phosphorus: average atomic mass 30.97, white
or red, solid, nonmetal, brittle, reactive, forms
compounds PCl3 and PCl5
• antimony: average atomic mass 121.8, silverywhite, solid, metalloid, brittle, reactive, forms
compounds SbCl3 and SbCl5
• sulfur: average atomic mass 32.07, yellow,
solid, nonmetal, brittle, reactive, forms
compound SCl2
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• selenium: average atomic mass 78.96, gray or
red, solid, nonmetal, brittle, reactive, forms
compound SeCl2
4. Possible answer: Nails are made of iron because
iron is hard and fairly stable in air and water.
Barium is too soft for a nail and it reacts easily
with water. Phosphorus is a brittle solid that is
difficult to shape and would break when struck
by a hammer. Phosphorus also reacts too easily
with air and water.
• iron: hard, heavy gray metal; reacts slowly
with water and oxygen
• barium: soft, silvery metal that reacts easily
with water and oxygen
• phosphorus: soft, white or red crystalline
solid, brittle, very reactive with water
and oxygen
5. a. CaS
b. The compound with sulfur will have more
mass for a given amount of calcium. The two
compounds have the same number of atoms,
but the atomic mass of sulfur is 32, and the
atomic mass of oxygen is only 16.
6. Possible answer: Dmitri Mendeleyev was the
youngest child in a large family. He and his
mother moved to St. Petersburg, Russia, when
his father died. After finishing school he began
teaching science while studying chemistry. He
became a professor of chemistry and wrote a
textbook called Principles in Chemistry. While
working on the book, he noticed patterns in the
properties of the elements. He made cards with
the symbols and properties of the elements and
began to arrange them. Based on the patterns
he saw in the card arrangements, Mendeleyev
developed his periodic table.
7. Possible answers:
a. Both versions arrange the elements in the
same order with the same atomic numbers.
The columns and rows include the same
elements in both versions. Elements are
arranged in order of increasing atomic mass.
b. The specific information about each
element, such as average atomic mass, differs
between the tables. The names and symbols
of elements 110 and higher are different.The
placement of the lanthanides and actinides
differs between the tables.
Living By Chemistry Solutions Manual
Lesson 10 Exercises
1. Within Group 1A, the elements tend to get
more reactive as you move from the top of the
column to the bottom.
Metallic characteristics tend to increase as you
move from the top of the table to the bottom.
The most reactive metals are located in the
lower left portion of the periodic table.
2. Possible answers (any 2):
• Reactivity of elements within a period
decreases from the left edge to the center and
then increases from the center to the right
side. However, the element at the far right side
of the period is very nonreactive.
• Elements change from metal to metalloid and
finally to nonmetal as you move left to right.
• Average atomic mass increases as you move
left to right.
• Phase changes from solid on the left to gas on
the far right.
• Heat conductivity decreases as you move left
to right.
• Conductivity decreases as you move left
to right.
3. a. Label groups as follows
• alkali metals: first column on left,
excluding hydrogen
• alkaline earth metals: second column
from left
• halogens: second column from right
• noble gases: last column on right
b. Label sections of table as follows
• main group elements: first two columns on
left and last six columns on right
(Groups 1A–8A)
• transition elements: the elements in the
B groups between the main group elements
• lanthanides: elements 57 through 70
• actinides: elements 89 through 102
4. Only two elements in Group 2A have average
atomic masses greater than 130—barium and
radium.
5. B, C, E, and F
6. A B, and E
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7. Copper and mercury are the least reactive. On
the periodic table the least reactive elements
(aside from the noble gases) are the transition
metals that are located in the center of the
table. The other elements listed are from more
reactive groups near the edge of the table: alkali
metals (potassium and rubidium), alkaline
earth metals (barium), and halogens (chlorine).
8. Possible answer: Copper and platinum, as
transition metals, are not very reactive and
therefore can be used to make jewelry. Sodium,
an alkali metal, is very reactive and not suitable
for making jewelry. Neon, a gas, cannot be used
to make jewelry.
Section II Review Questions
1. Possible answer: Gold, represented by the
symbol Au, is a transition metal that is a solid
at room temperature. It has an atomic number
equal to 79 and an average atomic mass of
197.0. Gold is nonreactive, a good conductor of
heat, and a good conductor of electricity. It has
similar properties to copper and silver.
2. Possible answer: During a chemical reaction
matter changes from one form to another, but
the total amount of each element in the matter
does not change. The products of a reaction,
such as the reactions in the Lab: The Copper
Cycle, can often be predicted based on the
materials that react.
3. Possible answer: A chemical formula is a symbol
that represents a compound. The chemical
formula shows what elements are in the
compound and the ratio in which the elements
combined. It can also show what physical form
the compound is in.
4. Possible answer: Tungsten might be useful
for a light bulb filament because it is a solid
metal. Bromine is unsuitable because it is a
liquid. Sulfur is unsuitable because it is not a
metal and therefore is a poor conductor and is
not malleable. Also, elements toward the left
of the periodic table are better conductors of
electricity than sulfur.
Project: Element Profile
A good report would include
• a definition and explanation of the law of
conservation of mass
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• a general description of the element and
its properties
• a list of all the common uses of an element
• a description of how abundant the element is
and how it is mined or extracted
• a description of the role the element plays in
the environment, or the environmental impact
of the element’s extraction and use in industry
• an analysis of how the element’s uses and
environmental roles relates to the law of
conservation of mass
• future projections of the availability and uses
of the element
Lesson 11 Exercises
1. When Thomson zapped atoms with electricity,
he found that a negatively charged particle was
removed. Because the solid sphere model does
not allow for particles splitting off atoms, he
created the plum pudding model.
If negatively charged parts of the atom can be
removed, then a separate part of the atom
must be positively charged. Thomson reasoned
that an atom consists of a positively charged
fluid that contains negatively charged particles
called electrons.
2. When Rutherford shot alpha particles at a thin
layer of atoms, most of them went straight
through, but some bounced back. The plum
pudding model does not have any solid parts,
nor does it have any concentrations of positive
charge that would repel the alpha particles. So,
Rutherford created the nuclear model.
Some of the positive particles were deflected
but most passed through. Rutherford reasoned
that the positively charged part of the atom
must make up a very small part of the total
volume. He called this concentration of positive
charge the nucleus and reasoned that the
electrons orbited within the vast empty space
surrounding the nucleus.
3. Bohr revised the nuclear model of the atom
when he noticed different atoms giving off
different colors of light when exposed to flame
or electric fields. Because the nuclear model
fails to account for this process, he created the
solar system model.
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Bohr suggested a model in which the electrons
orbit around the nucleus at different distances,
and proposed that these electrons have different
energies. Bohr reasoned that the different levels
of light energy emitted correspond to different
changes in energy that occur when electrons
move from an outer orbit to an inner orbit.
4. Both a proton and a nucleus are attracted to
a negative charge because they have a positive
charge. Because an electron has a negative
charge, it will be repelled by a negative charge.
Because neither a neutron nor an atom have
a charge, they will be neither attracted nor
repelled by a negative charge.
5. Possible answer: The two types of atoms could
have different amounts of positive fluid and
different numbers of electrons, as shown in this
illustration. Each atom would still have a net
charge of zero.
+
Hydrogen
2+
Helium
6. Possible answer: The electrons and protons can
exist together in a single mass as shown below.
The number of electrons and protons in each
atom is equal. The atom is held together by the
attraction between the positive protons and the
negative electrons.
7.
Electron
Proton
Neutron
8. a. The diameter of an atom is about 10–10 m.
b. The diameter of the nucleus is about 10–15 m.
Living By Chemistry Solutions Manual
c. The size difference can be calculated by
dividing the size of the atom by the size of
the nucleus.
10
​ ​m ​ 
_______
​ 1​015
 105
1​0​ ​m
 100,000
9. Possible answers:
a. In the nuclear model, all of the electrons
orbit the nucleus at the same distance. In the
solar system model, the electrons orbit the
nucleus at specific distances.
b. In both models, negatively charged electrons
revolve around a positively charged nucleus
in circular orbits. Most of the atom is
empty space.
c. To change the solar system model to a more
three-dimensional model, change some of
the electron orbits so that they are orbiting
the nucleus in different planes, similar to the
way the nuclear model is drawn.
10. Possible answers:
• Every compound is made of two or more
elements in specific proportions that never
change. Because these proportions are
always the same, there must be a basic unit
of each element.
• In Rutherford’s experiment, alpha particles
were deflected by particles in a sheet of gold
foil. The gold must be made of concentrated
bits of matter called atoms that contain mostly
empty space.
• Images of atoms have been made with
powerful scanning tunneling microscopes.
11.No, the Greeks were not correct. It is now
known that atoms are made of smaller particles
such as electrons, protons, and neutrons. Each
of these particles has a mass and a volume, so
they are matter.
12.Possible answer: Although the atomic theory
has existed for over 200 years, it has changed
with the addition of new discoveries. Each new
discovery leads to a new model that accounts for
the new information about how atoms function.
For example, the discovery of protons made
it necessary to revise the nuclear model to
account for small particles with a single unit of
positive charge.
Unit 1 Alchemy
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Although the question does not call for the
atomic theory as the basis for the example, it is
the obvious choice within this section. Other
examples, such as the theory of evolution, the
theory of plate tectonics, or models of motion
from Newton’s Laws to quantum mechanics,
could show the scientific process equally well.
Lesson 12 Exercises
1. The atomic number indicates the number of
protons in the nucleus of an atom.
2. The atomic mass is the mass of an atom. If the
mass is given in amu, then this number is equal
to the number of protons and neutrons in the
nucleus of the atom.
3. An atom that has 12 protons in its nucleus
has an atomic number of 12. The periodic
table indicates that element number 12
is magnesium.
4. The piece of information that identifies an
element is its atomic number, or the number
of protons in each atom of the element. The
number of protons in the nucleus is a constant
characteristic of all atoms of an element.
5. The atomic mass is the sum of the protons
and the neutrons in the nucleus of an atom.
Although boron and carbon each have six
neutrons, carbon has six protons while boron
only has five protons.
6.
Element
Sym.
at. #
#p
#e
#n
amu
nickel
Ni
28
28
28
31
58.69
neon
Ne
10
10
10
10
20.18
magnesium
Mg
12
12
12
12
24.31
phosphorus
P
15
15
15
16
30.97
zinc
Zn
30
30
30
35
65.38
7.
The information necessary to draw a model
of a neon atom is contained in the table for
Exercise 6. The model must show ten protons
and ten neutrons in the nucleus. The electrons
must be shown orbiting the nucleus. Two
electrons must be located on the innermost
orbit, and the other eight must be located on
the outermost orbit.
8. From lowest to highest number of protons:
• N: nitrogen, atomic number 7, 7 protons,
7 electrons, Group 5A
• Na: sodium, atomic number 11, 11 protons,
11 electrons, Group 1A
• Mg: magnesium, atomic number 12,
12 protons, 12 electrons, Group 2A
• S: sulfur, atomic number 16, 16 protons,
16 electrons, Group 6A
• Se: selenium, atomic number 34, 34 protons,
34 electrons, Group 6A
• Sr: strontium, atomic number 38, 38 protons,
38 electrons, Group 2A
Lesson 13 Exercises
1. Atomic number refers to the number of protons
in the nucleus of an atom. Atomic mass, when
expressed in amu, is the sum of the number of
protons and the number of neutrons.
2. Possible answer: The mass of an atom in amu
can be found by adding the number of protons
to the number of neutrons in that particular
atom. This number is always a whole number.
The average atomic mass given on the periodic
table is the average of the masses of all the
isotopes in a large sample of that element. The
periodic table in the textbook lists the average
atomic mass to four significant digits.
3. Possible answer: The isotopes differ from
one another in the number of neutrons in
their nuclei. Each potassium isotope has
19 protons, but potassium-39 has 20 neutrons,
potassium‑40 has 21 neutrons, and
potassium‑41 has 22 neutrons. The isotopes
40
  K,
   and 41
 K.
are 39
19  19 K,
19  
4. a. Fluorine-23 has 9 protons, 14 neutrons, and
9 electrons.
 
b. 59
Co
   has 27 protons, 32 neutrons,
27
and 27 electrons.
10
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LBC1eSM_01.indd 10
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c. Molybdenum-96 has 42 protons,
54 neutrons, and 42 electrons.
5. a. 58 amu
58
b.  
Fe
  
26
6. a. 30.97 amu
b. 15
c. Because the average atomic mass is just
slightly less than 31, a reasonable prediction
is that the most common isotope is
phosphorus-31.
7. Assume that a sample of 100 atoms would
contain 76 chlorine-35 atoms and
24 chlorine-37 atoms.
average atomic mass  ______________
  total mass
  
   
number of atoms
(76)(35 amu) + (24)(37 amu)
 ________________________
 
   
 
  
100
 35.48 amu
8. Assume that a sample of 1000 atoms
would contain 76 lithium-6 atoms and
924 lithium-7 atoms.
average atomic mass  ______________
  total mass
  
   
number of atoms
(76)(6 amu) + (924)(7 amu)
 _______________________
 
   
 
  
1000
 6.920 amu
9. Nitrogen has an atomic number of 7. The only
isotope symbol of the three choices that has
  N.
an atomic number of 7 is 14
7  The correct
answer is B.
Lesson 14 Exercises
1. Possible answer: An element is a fundamental
building block of matter. An atom is the
smallest possible unit of an element. An atom is
the smallest unit of an element that still has the
same characteristics as the element.
2. Possible answer: An isotope is an atom with a
specific number of protons and neutrons. The
word atoms can refer to a group of atoms with
different mass numbers.
3. Stable isotopes are the black and pink boxes on
the graph in the textbook that show isotopes
for the first 95 elements.
• Oxygen has 3 stable isotopes.
• Neodymium has 5 stable isotopes.
Living By Chemistry Solutions Manual
• Copper has 2 stable isotopes.
• Tin has 10 stable isotopes.
4. For each isotope, determine the number of
protons and neutrons in the isotope. Then look
at the corresponding coordinates on the graph
showing isotopes for the first 95 elements to
see if there is either a black box, pink box, or a
white box. If a box is present, then the element
is found in nature.
 Mg.
• A black box at (12, 12) represents 24
  
12
  Br.
• A pink box at (35, 46) represents 81
35 
 Nd.
• No box is present at (60, 92) for 152
60  
 Pt.
• A black box at (78, 117) represents 195
78  
238
• A white box at (92, 146) represents  
  
92U.
Uranium-238 is naturally occurring even
though it is not stable.
5. The diagonal line on the graph represents
isotopes that have equal numbers of protons
and neutrons, because the line passes through
points that have the same x- and y-coordinate.
6. a. Possible answer: helium-4,  42He;
  
10
 
 O
boron-10, B;
   and oxygen-16, 16
  
5
8
Any three isotopes that fall on the diagonal
line are acceptable. The mass number will be
twice the atomic number.
40
b. Possible answer: calcium-40,  
   and
20Ca
42
 
calcium-42, Ca
  
20
Any two isotopes that have the same atomic
number, representing the same element, are
acceptable.
19
c. Possible answer: fluorine-19,  
   and
9F
20
 
neon-20, 10Ne
  
Any two isotopes with the same variation
between their mass number and atomic
number are acceptable.
 Zn
d.Possible answer: zinc-70, 70
and
30  
70
 
germanium-70, 32Ge
  
Any two isotopes with the same mass
number are acceptable.
Unit 1 Alchemy
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 Ca
7. No stable isotopes exist beyond 40
20   that
have equal numbers of protons and neutrons.
The assumption must be made that a stable
isotope would occur naturally if it existed
(and therefore be plotted on the graph of the
isotopes of the first 95 elements).
8.
Oxygen-16
Oxygen-17
proton
neutron
electron
proton
neutron
electron
The possible elements are technetium
(atomic number 43), promethium (atomic
number 61), and any elements with an
atomic number greater than 83 except
thorium (atomic number 90). Each ratio
is determined by dividing the number of
neutrons by the number of protons.
10.Stable elements with 90 neutrons can have
62, 63, 64, or 66 protons. These elements
are samarium, europium, gadolinium, and
dysprosium. The assumption must be made
that a stable isotope would occur naturally
if it existed.
11.No, an isotope with 60 protons and a mass
of 155 would have 95 neutrons. The graph of
isotopes of the first 95 elements indicates that
there is not a stable isotope that has 60 protons
and 95 neutrons.
12.According to the graph of isotopes of the first
75
95 elements  
   is an isotope of arsenic that
33Ar
112
  ?  are not
 ?,
    and 260
occurs in nature. 162
88
63   56?,
likely to occur in nature.
13. C
Oxygen-18
proton
neutron
electron
14. B
Lesson 15 Exercises
1. A nuclear reaction is a change in the nucleus
of an atom.
Each drawing should have 8 protons and
8 electrons, 2 in the inner orbit and 6 in
the outer orbit. The only difference should
be in the number of neutrons represented
in the nucleus.
9. Possible answer:
• polonium: polonium-209 (1.49) and
polonium-210 (1.50)
• astatine: astatine-210 (1.47) and
astatine-211 (1.48)
• radon: radon-211(1.45), radon-220 (1.56),
and radon-222 (1.58)
• francium: francium-223 (1.56)
• radium: radium-223 (1.53), radium-224
(1.55), radium-226 (1.57), and
radium-228 (1.59)
12
Unit 1 Alchemy
LBC1eSM_01.indd 12
2. Possible answer: In alpha decay, a nucleus
emits a particle made up of two protons and
two neutrons. In beta decay, a nucleus emits an
electron. In alpha decay, the atomic number
decreases by two and the atomic mass decreases
by four. In beta decay, the atomic number
increases by one and the atomic mass
remains unchanged.
3. Possible answer: Gamma radiation is the most
harmful because it has the most power to
penetrate into living tissues and cause damage.
This answer can be inferred from the diagram
that shows the penetrating power of different
kinds of radioactive decay. However, alternate
answers are also acceptable. Alpha radiation is
very dangerous if an alpha-emitting substance
is ingested. Beta radiation can ionize atoms,
while gamma radiation cannot, and ionization
of body materials can lead to severe damage.
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4. The mass of the atom changes during alpha
decay because the nucleus loses two neutrons
and two protons, which have a combined mass
of 4 amu.
5. The mass of the atom does not change during
beta decay. The nucleus loses one electron,
which has a mass that is a tiny fraction of
the mass of the nucleus. The conversion of
a neutron into a proton does not change the
mass because neutrons and protons have nearly
identical masses.
6. The alpha particle is emitted from the nucleus
and consists only of protons and neutrons.
Because it has two positively charged particles
but no negatively charged particles, the alpha
particle has a net positive charge of 2 and is
not a neutral atom.
42
7. A. calcium-42,  
   ✓
20Ca
131
B. xenon-131,  
   ✓
54Xe
 Mg
C. magnesium-24, 24
✓
12  
52
D. cobalt-52,  
  
27Co
 Os
8. A. osmium-171, 171
76   ✓
 Sm
B. samarium-145, 145
✓
62  
 Np
C. neptunium-237, 237
✓
93  
228
D. radium-228,  
  
88Ra
9. The age of an object can be determined by the
amount of carbon-14 found in a sample of the
object relative to the amount of stable carbon
in the sample. Objects that can be dated using
carbon dating are composed partially of carbon,
which means that they are usually the remains of
living organisms. The wooden blade of the axe,
the ashes, and the jawbone originated in living
organisms. The clay pot and the arrowhead are
both composed mainly of other elements.
10.Possible answer: According to the graph of
the radioactive decay of carbon-14, 67% of
the original amount of carbon-14 will remain
after about 3500 years. Sources of error in this
determination are the ability to read the data
value on the graph, the measurement of the
amount of carbon-14 remaining in the sunken
ship, and the contamination of the sample due
to being underwater for thousands of years.
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11. C
12. C
Lesson 16 Exercises
1. Possible answers (any 4):
• In alpha decay, a nucleus emits a particle
consisting of two protons and two neutrons.
The atomic number decreases by two and the
atomic mass decreases by four.
• In beta decay, a nucleus emits an electron. The
atomic number increases by one as one of the
neutrons becomes a proton. The atomic mass
does not change.
• I n nuclear fission, a nucleus splits apart to form
the nuclei of two or more lighter elements.
• In nuclear fusion, two nuclei combine to form
the nucleus of a heavier element.
• Nucleosynthesis is the process of forming
elements inside stars through nuclear chemistry.
• A nuclear chain reactions is a series of nuclear
reactions when particles emitted by one fission
reaction strike other nuclei.
2. A nuclear chain reaction is a sequence of
nuclear fission reactions occurring when a
particle strikes a nucleus causing it to break
apart and form more particles that strike other
nuclei, breaking them apart.
3. The atomic number of cerium, Ce, is 58. Beta
decay increases the atomic number by one,
forming praseodymium, Pr. The atomic mass
does not change.
141
141
  Ce
 
​ 0​e     
  
58  → 1
59Pr
4. The atomic number of platinum, Pt, is 78.
Alpha decay decreases the atomic number by
two, forming osmium, Os. The atomic mass
decreases by four, from 191 to 187.
191
 Pt
78  
 Os
→ 4 2He
    187
76  
4 
 Cr
 Fe
5. Possible answer: 50
   → 54
24    2He
26  
The two nuclei chosen for the example must
have atomic numbers and atomic masses that
sum to the atomic number of iron, which is 26,
and atomic mass of iron-54, which is 54.
6. a. The addition of a neutron to uranium-235 is
1 
 U
 U.
shown by the equation 235
   → 236
92    0n
92  
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b. Krypton-94 has 36 protons and barium-139
has 56 protons.
c. A uranium atom has 92 protons and the
reaction products have 92 protons, so no
protons were lost.
7. Possible answer: Inside a nuclear power plant,
uranium-235 is concentrated into rods and
submerged in water. The atoms break apart
when a neutron strikes them. More neutrons
are produced during the reaction and they
strike other uranium-235 atoms. These fission
reactions produce heat that is used to convert
water into steam. The steam turns a turbine to
generate electric power.
Control rods are made of material that absorbs
the neutrons without breaking apart. Raising
and lowering the rods in the water controls the
rate of the nuclear reactions by changing the
amount of neutrons absorbed.
Section III Review Questions
1. Possible answer: An atom changes identity
when the number of protons in its nucleus
changes. Processes in which this can occur
are radioactive decay, fission, and fusion. In
radioactive decay, emission of an alpha particle
decreases the atomic number by two, while
emission of a beta particle increases the atomic
number by one. Nuclear fission is the process
in which a nucleus breaks apart, forming two
or more smaller nuclei. In nuclear fusion, two
nuclei join together to form one larger nucleus.
2. Possible answer: Elements are formed in nature
by nuclear fusion. Most of the elements found
on Earth are the products of fusion reactions in
stars that exploded billions of years ago. After
forming, these elements can decay into other
elements through radioactive decay.
3. The atomic number of cadmium, Cd, is 48.
Beta decay increases the atomic number by
one, forming indium, In. The atomic mass
does not change.
113
 Cd
48  
14
Unit 1 Alchemy
LBC1eSM_01.indd 14
 
 In
→ 1
​ 0​e    113
49  
4. Possible answer: The atomic number of copper
is 29 and the atomic number of gold is 79.
Gold only has one naturally occurring stable
isotope, which is gold-197. The most common
isotope of copper is copper-63. Start by writing
the equation.
63
 Cu
29  
197
 ? ?  ? → 
  
79 Au
The unknown element must have an atomic
number of 79  29  50 and a mass number of
197  63  134. Tin, Sn is the element whose
atomic number is 50.
197
63
134
 Cu
 
   →  
  
29  
50Sn
79 Au
The equation above is not plausible because
tin-134 is not a naturally occuring isotope
of tin. Copper cannot be fused directly with
another atom to make gold because there is
no combination of isotopes of copper and tin
that have enough neutrons to form a stable
isotope of gold.
Project: Nuclear Power
A good report would include
• a description of how a nuclear reaction
produces energy
• a description of how the heat product in
nuclear reactions is converted into electricity
• a drawing of the inside of a reactor core
and how the steam turns a turbine inside
a generator
• a list of the advantages and disadvantages of
nuclear power when compared to fossil fuels
and alternative energy sources
• an opinion on whether nuclear power will be
and should be an important source of energy
in the future
Lesson 17 Exercises
1. The color of the flame produced during a flame
test is a characteristic of particular metallic
elements. When a compound containing one of
the metallic elements is heated, its atoms emit
light of a specific color.
2. When a compound is heated, some of the
electrons in the metallic atoms gain energy and
move farther away from the nucleus. When the
electrons move back to their original distance,
they release energy in the form of colored light.
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3. Possible answer: Fireworks are colorful because
they are made using metallic compounds
that emit visible light during the explosions.
Electrons of the metal atoms become excited
when they are heated and the atoms release
energy as light when the electrons return to
their original state. Salts of various metals
produce the range of fireworks colors:
• red: lithium or strontium
• orange: calcium
• yellow: sodium
• green: barium
• blue: copper
4. The flame for sodium hydroxide will be yelloworange because the metal atom determines the
color. Sodium atoms emit a yellow-orange color
when placed in a flame.
5. Possible answers (any 2):
• Red fireworks could contain lithium chloride
and purple fireworks could contain a mixture
of lithium chloride and copper chloride.
• Red fireworks could contain lithium sulfate
and purple fireworks could contain a mixture
of lithium sulfate and copper sulfate.
• Red fireworks could contain lithium nitrate
and purple fireworks could contain a mixture
of lithium nitrate and copper nitrate.
A red color in fireworks would result from
using a lithium salt. A purple color would
result by mixing compounds that would
produce red and blue colors separately. Any
mixture of lithium and copper salts would
produce purple fireworks.
6. Possible answer: The Lab: Flame Tests involved
the performance of a flame test on five different
compounds containing copper: copper nitrate,
copper sulfate, copper chloride, copper wire,
and a copper-coated penny. Each compound
produced a blue-green flame when heated
by the Bunsen burner. Since the presence of
copper is the only thing these compounds have
in common, the copper is responsible for the
blue-green flame.
7. No, the flame color of each nitrate compound
is different and matches the flame color of the
metal in the compound. This indicates that
the nitrate is not responsible for the color of
the flame.
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8. No, the form of the sodium chloride does not
affect the results of the flame test because the
atoms do not emit light until they become very
hot. The water will evaporate from the aqueous
solution before the sodium chloride becomes
hot enough to emit light.
9. The flame color produced by each compound
can be determined by matching the metallic
element in the compound with the flame color
produced by compounds with that element.
a. yellow-orange
b. green
c. pink-lilac
d. pink-lilac
e. green
10. C
11. D
Lesson 18 Exercises
1. For main group elements, the number of shells
containing electrons is equal to the period
number. All of the shells, except the highest,
are completely filled. The group number
determines the number of electrons in the
outermost shell.
2. For elements in the main group, the number of
valence electrons is equal to the group number.
3. Possible answer: Beryllium, magnesium, and
calcium are all alkaline earth metals located in
Group 2A. These three elements have similar
chemical and physical properties because they
have two valence electrons.
4.
Core electrons
5
Valence electrons
Boron has an atomic number of 5, so it has five
total electrons. Boron is a Group 3A element in
the second period of the periodic table, so it has
three valence electrons in the second shell. The
first shell is filled with two core electrons.
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5. The number of core electrons does not change
across a period for main group elements.
6. a. Carbon has 6 electrons and silicon has
14 electrons.
b.
6
Carbon
14
Silicon
c. Carbon and silicon both have 4 valence
electrons.
d. Carbon has 2 core electrons and silicon has
10 core electrons.
e. Carbon and silicon have similar properties
because atoms of the two elements have the
same number of valence electrons.
7. a. Element number 17 is chlorine. It has
the chemical symbol Cl and is located in
Group 7A. This information comes directly
from square 17 on the periodic table.
b. The nucleus contains 17 protons. The
number of protons is equal to the
atomic number.
c. Possible answer: The average atomic mass of
chlorine to the nearest whole number is
35 amu. Therefore, the nucleus will have
35  17  18 neutrons. According to the
graph of isotopes of the first 95 elements,
chlorine-35 is a naturally occuring isotope.
d. The number of electrons in a neutral atom of
chlorine is 17. In a neutral atom, the number
of electrons equals the number of protons.
e. Chlorine has 7 valence electrons. The
number of valence electrons is equal to the
group number.
f. Chlorine has 10 core electrons. The number
of core electrons equals the difference
between the total number of electrons and
the number of valence electrons, or 17  7.
g. Possible answer (any 3 elements): Fluorine,
bromine, iodine, and astatine all have the
same number of valence electrons. All of
these elements are in Group 7A along with
chlorine.
16
Unit 1 Alchemy
LBC1eSM_01.indd 16
8. a. Element number 50 is tin. It has the chemical
symbol Sn and is located in Group 4A. This
information comes directly from square 50
on the periodic table.
b. T
he nucleus contains 50 protons. The number
of protons is equal to the atomic number.
c. Possible answer: The average atomic mass of
tin to the nearest whole number is
119 amu. Therefore, the nucleus will have
119  50  69 neutrons. According to the
graph of isotopes of the first 95 elements,
tin-119 is a naturally occuring isotope.
d. The number of electrons in a neutral atom
of tin is 50. In a neutral atom, the number of
electrons equals the number of protons.
e. T
in has 4 valence electrons. The number of
valence electrons is equal to the group number.
f. Tin has 46 core electrons. The number of core
electrons equals the difference between the
total number of electrons and the number of
valence electrons, or 50  4.
g. Possible answer (any 3 elements): Carbon,
silicon, germanium, and lead all have the
same number of valence electrons. All of these
elements are in Group 4A along with tin.
9. E
10. B
Lesson 19 Exercises
1. A cation is an ion that has a positive charge.
An anion is an ion that has a negative charge.
2. Noble gas envy is a term referring to the
tendency of atoms to gain or lose electrons to
obtain an electron configuration in which the
outer shell is completely filled. Noble gases
are the only elements with their outer shells
completely filled in their neutral state.
3. The atomic number of lithium is 3, so Li+
has 3 protons. Li+ is a cation formed when a
lithium atom loses one of its electrons, so Li+
has 2 electrons. The average atomic mass of
lithium to the nearest whole number is
7 amu. Therefore, the nucleus will have
7  3  4 neutrons. According to the graph of
isotopes of the first 95 elements, lithium-7 is a
naturally occuring isotope.
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4. Possible answer: Cl and Cl– are similar in that
they both have the same number of protons
and the same number of neutrons. But, Cl has
17 electrons and Cl– has 18 electrons. Cl is more
reactive because it is missing an electron in its
valence shell, while Cl– is more stable because it
has a full valence shell.
5. Possible answer: Be and Be2+ are similar in that
they have the same number of protons and the
same number of neutrons. But, Be has four
electrons and Be2+ has two electrons. Be is more
reactive because it has only two electrons in its
valence shell, while Be– is more stable because it
has a full valence shell.
6. The noble gas closest to magnesium is neon. A
magnesium atom loses two electrons to have an
electron arrangement similar to that of neon.
The closest noble gas may be in a different
period of the table, as shown in this exercise.
Neon has two fewer electrons than magnesium,
but argon, the noble gas in the same period as
magnesium, has six more electrons.
7. The noble gas closest to sulfur is argon. A sulfur
atom gains two electrons to have an electron
arrangement similar to that of argon.
8. Possible answers (any 4): N3–, O2–, F–, Na+,
Mg2+, Al3+
The elements that are close to neon on the
periodic table gain or lose electrons to have the
same electron structure as neon.
9. Possible answers (any 4): P3–, S2–, Cl–, K+, Ca2+
The elements that are close to argon on the
periodic table gain or lose electrons to have the
same electron structure as argon.
10.Arsenic is a Group 5 element so it has 5 valence
electrons. It will form an ion by adding three
electrons to have the same electron arrangement
as krypton. It has a charge of 3–. The symbol for
the arsenic ion is As3–.
11.The element that has 22 protons is identified on
the periodic table as titanium, Ti. Because the
ion has 22 protons and 18 electrons, it has a net
positive charge of 4. The number of neutrons is
not needed in order to determine the ion.
12.When chlorine gains an electron, it does not
become an argon atom because the ion still has
17 protons. It is the number of protons that
determines the identity of the element.
Living By Chemistry Solutions Manual
13.Elements on the right side of the table gain
electrons to have a noble gas arrangement.
They do not tend to lose electrons because the
charge would be too large.
14.In each period, ions on the left side have a
positive charge that increases toward the
center of the table. On the right side, ions have
a negative charge, which increases from the
second row from the right toward the center.
The element at the far right of a period does
not form ions.
15. B, D, and E
16. A, B, and E
Lesson 20 Exercises
1. The number of valence electrons can be used to
predict whether an atom will form a cation or
an anion, as well as the charge on the ion. Ionic
compounds form between cations and anions
in a ratio where the charges are balanced.
2. The rule of zero charge can be used to predict
the ratio of ions that will form a compound
that has no overall charge.
3. a. 1
b. 3
c. Lithium nitride has three lithium ions with
a charge of 1 and one nitride ion with a
charge of 3.
3(1)  (3)  3  (3)  0
d. Lithium has 1 valence electron. Nitrogen
has 5 valence electrons. So there are a total
of 8 valence electrons in Li3N.
4. a. 3
b. 3
c. Aluminum arsenide has one aluminum ion
with a charge of 3 and one arsenide ion
with a charge of 3.
(3)  (3)  0
d. Aluminum has 3 valence electrons. Arsenic
has 5 valence electrons.
5. a. KBr has one potassium ion with a charge
of 1 and one bromide ion with a charge
of 1.
(1)  (1)  0
b. CaO has one calcium ion with a charge of
2 and one oxide ion with a charge of 2.
(2)  (2)  0
Unit 1 Alchemy
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c. Li2O has two lithium ions with a charge of
1 and one oxide ion with a charge of 2.
2(1)  (2)  2  (2)  0
d. CaCl2 has one calcium ion with a charge
of 2 and two chloride ions with a charge
of 1.
(2)  2(1)  2  (2)  0
e. AlCl3 has one aluminum ion with a charge
of 3 and three chloride ions with a charge
of 1.
(3)  3(1)  3  (3)  0
6. a. Potassium, K, has 1 valence electron.
Bromine, Br, has 7 valence electrons.
b. Calcium, Ca, has 2 valence electrons.
Oxygen, O, has 6 valence electrons.
c. Lithium, Li, has 1 valence electron.
Oxygen, O, has 6 valence electrons.
d. Calcium, Ca, has 2 valence electrons.
Chlorine, Cl, has 7 valence electrons.
e. Aluminum, Al, has 1 valence electron.
Chlorine, Cl, has 7 valence electrons.
7. All three compounds violate the rule of
zero charge.
a. NaCl2 does not form because it has a net
charge of 1. The sodium ion has a charge
of 1 and each chloride ion has a charge
of 1.
(1)  2(1)  1  (2)  1
b. CaCl does not form because it has a net
charge of 1. The calcium ion has a charge
of 2 and the chloride ion has a charge
of 1.
(2)  (1)  1
c. AlO does not form because it has a net charge
of 1. The aluminum ion has a charge of 3
and the oxide ion has a charge of 2.
(3)  (2)  1
Lesson 21 Exercises
1. For main group elements, the group number
shows the number of valence electrons.
• Metal atoms lose all of their valence electrons
when they form an ion, adding a positive
charge for each electron lost.
• Nonmetal atoms gain enough electrons to
have eight valence electrons, adding one
negative charge for each electron gained.
18
Unit 1 Alchemy
LBC1eSM_01.indd 18
2. For main group elements, the periodic table is
used to determine the charge on each ion. Ions
combine to form ionic compounds in ratios
that have a total charge equal to zero.
3. a. LiCl is possible because the total of the
charges on the ions equals zero. The lithium
ion has a charge of 1 and the chloride ion
has a charge of 1.
(1)  (1)  0
b. LiCl2 is not possible because the total of the
charges on the ions equals 1.
(1)  2(1)  1  (2)  1
c. MgCl is not possible because the total of the
charges on the ions equals 1. Magnesium
ions have a charge of 2.
(2)  (1)  1
d. MgCl2 is possible because the total of the
charges on the ions equals zero.
(2)  2(1)  2  (2)  0
e. AlCl3 is possible because the total of the
charges on the ions equals zero. Aluminum
ions have a charge of 3.
(3)  3(1)  3  (3)  0
4. Possible answer (any 6): Sodium chloride, NaCl,
has 8 valence electrons; Calcium oxide, CaO,
has 8 valence electrons; Rubidium iodide, RbI,
has 8 valence electrons; Potassium bromide,
KBr, has 8 valence electrons; Sodium fluoride,
NaF, has 8 valence electrons; Magnesium oxide,
MgO, has 8 valence electrons; Strontium sulfide,
SrS, has 8 valence electrons; Calcium sulfide, CaS,
has 8 valence electrons.
Any combination of a Group 1A metal with a
Group 7A nonmetal, or a Group 2A metal with
a Group 6A nonmetal, or a Group 3A metal
with a Group 5A nonmetal is correct.
5. Possible answer (any 3): Sodium oxide, Na2O,
has 8 valence electrons; Lithium oxide, Li2O,
has 8 valence electrons; Rubidium sulfide, R​b2​ ​S,
has 8 valence electrons; Potassium sulfide, KS,
has 8 valence electrons.
Any combination of a Group 1A metal with a
Group 6A nonmetal is correct.
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6. Possible answer (any 3): Magnesium chloride,
MgCl2, has 16 valence electrons; Calcium
fluoride, CaF2, has 16 valence electrons;
Barium iodide, BaI2, has 16 valence electrons;
Strontium bromide, SrBr2, has 16 valence
electrons.
Any combination of a Group 2A metal with a
Group 7A nonmetal is correct.
7. a. AlBr3, aluminum bromide
b. Al2​​S3, aluminum sulfide
c. AlAs, aluminum arsenide
d. Na2S, sodium sulfide
e. CaS, calcium sulfide
f. Ga2​​S3, gallium sulfide
8. a. Mg2+, O2−, MgO
b. Rb+, Br−, RbBr
c. Sr2+, I−, SrI2
d. Be2+, F−, BeF2
e. Al3+, Cl−, AlCl3
f. Pb4+, S2−, PbS2
Lesson 22 Exercises
1. A polyatomic ion is an ion that consists of two
or more elements.
2. An ionic compound has a polyatomic ion if there
are more than two elements in the compound.
3. a. ammonium chloride
b. potassium sulfate
c. aluminum hydroxide
d. magnesium carbonate
4. a. Li2S​O​4​
b. KOH
c. Mg(NO3​​)2
d. (NH4​​)2S​O​4​
5. The chemical formula of the cyanide ion must
be CN because sodium, Na, forms the metal
cation. Sodium is in Group 1A, so its ion has
a charge of 1. Because the ions are combined
in a 1:1 ratio, the cyanide ion must have a
charge of 1.
Living By Chemistry Solutions Manual
6. The chemical formula clearly shows PO4 as the
polyatomic ion. Calcium, Ca, is in Group 2A, so
it forms a cation with a charge of 2. The ions
combine in a 3:2 ratio. Because the total charge
on the cations is 3  (2)  6, the total charge
on the anions should be −6. Each phosphate
anion must have a charge of (6)  2  3.
7. B. KSO4 does not form because it has a net
charge of 1. The potassium ion has a charge
of 1 and the sulfate ion has a charge of 2.
(1)  (22)  1
Lesson 23 Exercises
1. The Roman numeral indicates the charge on
the transition metal cation in the compound.
2. Determine the total charge on the anions in the
compound. The total charge of the cations is
the opposite of the charge on the anions. Divide
by the number of cations in the chemical
formula to find the charge of each cation.
3. a. 2, mercury (II) sulfide
b. 2, copper (II) carbonate
c. 2, nickel (II) chloride
d. 3, cobalt (III) nitrate
e. 2, copper (II) hydroxide
f. 2, iron (II) sulfate
4. a. Cu2+, S2−, CuS
b. Ni2+, NO3−, Ni(NO3​​)2
c. Fe2+, CO32−, FeCO3
d. Co2+, SO42−, CoSO4
e. Fe3+, CO32−, Fe2(CO3​​)3
f. Cr6+, O2−, CrO3
5. Co3(PO4​​)2
Lesson 24 Exercises
1. Electron subshells are divisions within a specific
electron shell of an atom.
2. An electron configuration is a shorthand
notation used to show the position of electrons
within shells and subshells of an atom.
Unit 1 Alchemy
19
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3. As the number of electrons in an element
increases, they are added in a specific sequence
that is illustrated by the position of the element
on the periodic table. Each section of the table
corresponds to a particular subshell of electrons.
4. • The shell n  1 has one subshell.
• The shell n  2 has two subshells.
• The shell n  3 has three subshells.
• The shell n  4 has four subshells.
The number of subshells that a shell n has is
equal to n.
5. The sum of the subshells of the shells n  1, 2,
3, 4, and 5 is 1  2  3  4  5  15.
6. a.
b.
10
11
c.
d.
7. 4p
8. Possible answer: gold
You can accept any element that has an atomic
number of 57 or greater as a correct answer.
9. a. 1​s2​ ​2s22p63s23p1
b. Element 13 has 3 valence electrons because
it has three electrons in the outer shell, n  3.
c. Element 13 has 10 core electrons because it
has two shells filled completely: n  1 with
2 electrons and n  2 with 8 electrons.
10.Argon, krypton, and xenon have similar
properties because they all have the same
number of valence electrons in their outermost
shells. The additional core electrons do not
affect the properties of the elements very much.
LBC1eSM_01.indd 20
13. a. chromium
d. cesium
b. silicon
e. lead
c. nitrogen
f. silver
1. Valence electrons are important because they
are the outermost part of an atom and will
interact with other atoms. This interaction is
what determines the properties of an element.
6
Unit 1 Alchemy
12.Possible answer: Add the total number of
electrons in the configuration and look up
the atomic number. Find the location on the
periodic table that corresponds to the end of
the electron configuration.
Section IV Review Questions
23
20
11. a. 1s22s22p4, [He] 2s22p4
b. 1s22s22p63s23p5, [Ne] 3s23p5
c. 1s22s22p63s23p64s23d6, [Ar] 4s23d6
d. 1s22s22p63s23p64s2, [Ar] 4s2
e. 1s22s22p63s2, [Ne] 3s2
f. 1s22s22p63s23p64s23d104p65s24d9, [Kr] 5s24d9
g. 1s22s22p63s23p2, [Ne] 3s23p2
h. 1s22s22p63s23p64s23d10​​4p65s24d105p66s24f 14
5d10, [Xe] 6s24f 145d10
2. Ionic compounds are combinations of cations
and anions that are bound together by the
electrical attraction of their opposite charges.
They form when electrons are transferred
between atoms leaving each resulting ion with a
noble gas arrangement.
3. As the number of electrons in an element
increases, they are added in a specific sequence
that is illustrated by the position of the element
on the periodic table. Each section of the table
corresponds to a particular subshell of electrons.
4. 1s22s22p63s23p1, [Ne] 3s23p1
5. a. The anion is Mg2+ and has a charge of 2.
The cation is Cl− and has a charge of 1.
b. The anion is Ca2+ and has a charge of 2.
The cation is NO2− and has a charge of 1.
6. a. Na2SiO3, NaClO2, NaHCO3
b. CaSiO3, Ca(ClO2​​)2, Ca(HCO3​​)2
Lesson 25 Exercises
1. A substance is insoluble if it fails to dissolve in a
particular solvent.
The word insoluble does not imply that the
solvent is water. A substance that does not
dissolve in water is said to be insoluble in water.
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2. Possible answer: Electrical conductivity can be
tested by setting up a simple electrical circuit.
When the circuit is complete, a light bulb that is
part of the circuit will light up. If the circuit is
interrupted by a substance that does not conduct
electricity, the light bulb will not light up.
3. Possible answer: The substance is most likely an
ionic compound. Many compounds dissolve in
water but electrical conductivity in solution is a
characteristic of compounds that separate into
ions, such as ionic compounds.
Although there are exceptions, most ionic
compounds dissolve in water. Ionic solutions
always conduct electric current because the ions
are mobile in the solution.
4. No, though ionic compounds generally contain
metals, they do not conduct electricity in their
solid form.
Substances that are composed only of metals
always conduct electricity. However, in a solid
ionic compound, where a metal is bonded
with a nonmetal, the charged ions are locked
into position so they cannot move freely and
carry electricity.
5. No, though ionic compounds generally do not
conduct electricity as solids, they do conduct
electricity as aqueous solutions.
In solution, the ions of an ionic compound are
able to move around, so they can carry electric
charges from one place to another.
6. Possible answers:
a. Acetone is not likely to conduct electricity
either in solution or in its pure form because
it does not contain any metallic elements.
Acetone will probably dissolve in water
because compounds composed only of
carbon, hydrogen, and nitrogen usually
dissolve in water.
b. Titanium is a metallic element, so it conducts
electricity and does not dissolve in water.
c. Lithium nitrate is an ionic compound, so
it dissolves in water and does not conduct
electricity in its solid form. Once dissolved, it
will conduct electricity.
d. Bronze is a mixture that is composed only
of metallic elements. Therefore, it conducts
electricity and does not dissolve in water.
Living By Chemistry Solutions Manual
Lesson 26 Exercises
1. The atoms that make up substances are held
together by chemical bonds. The bond is an
attraction between the positively charged
nuclei of atoms and the valence electrons of
other atoms.
2. Possible answers:
• In ionic bonding, one or more valence
electrons are transferred from a metal atom
or group of atoms to a nonmetal atom or
group of atoms, forming a positively charged
cation and a negatively charged anion. The
bond forms due to the attraction of the
opposite charges.
• In metallic bonding, valence electrons from
all of the metal atoms move freely among the
cations that are formed when the electrons
leave the metal atoms. The bond forms
because of the attraction of the positively
charged cations to the sea of negatively
charged electrons.
• In network covalent bonding, valence
electrons from each nonmetal atom are shared
with all of the atoms around it. The structure
of the substance is very rigid since each atom
bonds with multiple neighboring atoms.
• In molecular covalent bonding, valence
electrons from a nonmetal atom are shared
with other individual atoms, forming groups
with a specific number and arrangement of
atoms, called molecules.
3. a. Because zinc consists entirely of metal atoms,
it is held together by metallic bonds.
b. Propane is made entirely of nonmetal
atoms, so it is held together by molecular
covalent bonds.
c. Calcium carbonate consists of the metal
calcium and the polyatomic ion carbonate.
Therefore the compound is an ionic compound
that is held together by ionic bonds.
4. Possible answer:
A. Hair gel would probably consist of molecular
covalent bonds. Hair gel is soft and
malleable, dissolves in water, and is easily
separated into smaller portions, so it is likely
to be molecular.
Unit 1 Alchemy
21
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B. A silver bracelet has metallic bonds. A
silver bracelet is made entirely of metal, so
its atoms will be held together by metallic
bonds. It is hard and bendable and conducts
electricity.
C. Motor oil would probably consist of
molecular covalent bonds. Motor oil is a
viscous liquid, and liquids that are not salts
in an aqueous solution are usually molecular.
D. Baking soda is the only one of these
substances that could have ionic bonds. It
is a solid crystalline material that dissolves
easily in water. If it contains metal and
nonmetal atoms, it is probably held together
by ionic bonds.
5. NO2 is a gas that is made up of nonmetal
atoms, so it has molecular covalent bonds.
e. Copper sulfate, CuSO4, is an ionic
compound, so it will dissolve in water.
Lesson 27 Exercises
1. Possible answers (any 3):
• finding pure metals in nature
• heating ionic compounds to separate
the metal
• extracting metals with electricity
• reusing and recycling discarded metals
2. Possible answer: Place two nickel strips in a
beaker of copper chloride solution. Connect
the strips to the two terminals of a battery.
Allow the battery current to flow until the
strip connected to the negative terminal of the
battery has become plated with copper.
Battery
6. E
7. Possible answer: Drop the mixture into a
beaker of water. The ionic bonds of sodium
chloride break apart in water, causing the solid
to dissolve. Carbon, held together by network
covalent bonds, does not dissolve in water, and
so can be filtered from the solution.
8. Copper metal can be shaped into a wire easily
because of its metallic bonds. Metals are
malleable and ductile. Copper chloride, as
an ionic compound, is brittle and cannot be
shaped into a wire. The ions in copper chloride
are held in position relative to one another by
strong ionic bonds.
9. Carbon is a solid because many carbon atoms
are held together in a large array by network
covalent bonds, such as in diamond. Gases are
single atoms or molecules held together by
molecular covalent bonds.
10. Possible answers:
a. Calcium, Ca, is held together by metallic
bonding so it will not dissolve in water.
b. Sodium nitrate, NaNO3, is an ionic
compound, so it will dissolve in water.
c. Silicon, Si, is a solid held together in a large
array by network covalent bonds, similarly to
carbon. It will not dissolve in water.
d. Methane, CH4, is a liquid held together by
molecular covalent bonds, so it will probably
dissolve in water.
22
Unit 1 Alchemy
LBC1eSM_01.indd 22
Nickel
strips
Copper
deposits
here
Copper
chloride solution
Diagrams should include a voltage source
(a battery), a solution of copper chloride
with two nickel strips in it, and connections
between each strip and one of the terminals
on the battery.
3. Possible answer: Attach the coated object
to the positive terminal of a battery in an
electroplating circuit. When an object is
attached to the positive terminal, electrons flow
from the object, forming cations. The metal ions
are no longer attracted to the coated object, and
they enter the solution.
4. A good lab report will contain
• a title (Lab: Electroplating)
• a statement of purpose (Possible answer: To
demonstrate how metals can be extracted
from an ionic compound dissolved in water)
• a procedure (a summary of the steps followed
in the experiment)
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• results (Check student observations to make
sure they address all of the observation
questions in the lab.)
• a conclusion (The conclusion should include
a statement about the attraction of the metal
cations to the metal strip. Possible answer:
When an ionic compound is dissolved in
water, running an electric current through
two metal strips and the solution will cause
the metal cations to deposit on the negatively
charged metal strip.)
5. The copper sulfate solution is composed of
cations, Cu2+, and anions, SO4−, dissolved in
water. The only thing that is added to the solution
during the experiment is a stream of electrons.
When the electrons are added to the copper ions,
copper atoms, Cu, are formed on the metal
strip. This indicates that the Cu2+ ions are
simply copper ions that are missing electrons.
6. Possible answer: The mass of the negatively
charged nickel strip should increase as it is
plated with copper. There is no change to the
nickel itself, but as a layer of copper forms on
top of the nickel, the mass will increase by the
mass of the copper plating.
7. Possible answer: Nickel cannot change into
copper unless the number of protons in the
nucleus changes. The plating apparatus only
adds electrons to the nickel strip, causing the
plating to occur. Adding electrons does not
change the nucleus, so it cannot change the
identity of the atoms.
You cannot be sure simply from observation
that the strip is copper-coated nickel and not
pure copper. Reversing the experiment only
proves that the copper appears and disappears
on the strip. Observations must be taken into
account along with knowledge about the
structure of atoms. Taking the copper-plated
strip and cutting it or measuring its density to
prove that the nickel is still there is not a valid
answer because it does not explain why the
nickel had to remain intact.
Section V Review Questions
2 . Possible answer: Determine whether the
material conducts electric current, whether it
dissolves in water, and if it does, whether the
solution conducts electric current.
• If a material does not conduct electricity
unless it is in solution, it has ionic bonding.
• If a material conducts electricity but does not
dissolve, it has metallic bonding.
• If a material does not conduct electricity even
when in solution, it has molecular covalent
bonding.
• If a material does not conduct electricity and
does not dissolve, it has network covalent
bonding.
These are only general guidelines and there are
exceptions to the rules listed above.
3. Possible answer: Isopropanol will not conduct
electricity because compounds with only
nonmetal atoms have covalent bonding and do
not conduct electricity. Also, isopropanol is a
liquid at room temperature, which means it is
not an ionic compound.
4.
Dissolves
Does not
dissolve
Conducts
ionic (conducts
in solution)
metallic
Does not
conduct
molecular
covalent
molecular covalent
network covalent
Molecular covalent bonds appear in two boxes
because some molecular compounds dissolve
and others do not.
Unit 1 Review Exercises
1. Possible answer: An element is the basic
building block of compounds. An element has
only one type of atom, while a compound has
at least two types of atoms held together by
chemical bonds.
An alternative answer is that a compound can
be broken down into simpler substances, but an
element cannot.
1. Possible answer: While it is not practical to try
to make gold, many substances that are quite
valuable can be made through chemistry.
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Unit 1 Alchemy
23
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2. D  __
 m , so
V
m
__
V       m • __
 1  
D
D
lead: V  20.0 g • _____
 1 mL 
   1.75 mL
11.4 g
aluminum: V  20.0 g • _____
 1 mL   7.41 mL
2.7 g
The aluminum object takes up more space.
3. a. Lithium, Li, has atomic number 2 and is in
Group 2A. It has 2 protons and 2 electrons.
b. Bromine, Br, has atomic number 35 and is in
Group 7A. It has 35 protons and 35 electrons.
c. Zinc, Zn, has atomic number 30 and is in
Group 2B. It has 30 protons and 30 electrons.
d. Sulfur, S, has atomic number 16 and is in
Group 6A. It has 16 protons and 16 electrons.
e. Barium, Ba, has atomic number 56 and is in
Group 2A. It has 56 protons and 56 electrons.
f. Carbon, C, has atomic number 6 and is in
Group 4A. It has 6 protons and 6 electrons.
4. Nuclear fission occurs when a nucleus breaks
apart to form two nuclei with smaller atomic
numbers than the original nucleus. Nuclear
fusion occurs when two nuclei join together to
form a nucleus with a greater atomic number.
5. An isotope is an atom of an element with a
specific number of neutrons in its nucleus.
You can predict the most common isotope
by rounding the average atomic mass of the
element to the nearest whole number.
For some elements having multiple isotopes
that are found in nature, the average atomic
mass does not reflect the common isotope.
However, the procedure described above is the
best for predicting the common isotope using
only the periodic table.
6. Possible answer:
• If both atoms are metal atoms, then the atoms
will form a metallic bond.
• If one atom is a metal and the other atom is a
nonmetal, then the two atoms might form an
ionic bond.
• If both atoms are nonmetal atoms, then the
atoms might form a covalent bond.
• If either atom is a noble gas, the atoms will
probably not form any bond.
24
Unit 1 Alchemy
LBC1eSM_01.indd 24
7. Cations are ions that have lost electrons,
causing them to have a positive charge. Anions
are ions that have gained electrons, causing
them to have a negative charge.
8. • metals: Na, Sr, Mg, Cu
• nonmetals: S, Cl, Se, I
• Possible answer (any 3): sodium chloride,
NaCl; magnesium iodide, MgI2; strontium
sulfide, SrS; and copper (II) chloride, CuCl2.
Any combination of metal and nonmetal
elements can be examples of ionic compounds
as long at the ratio of metal to nonmetal in
the chemical formula indicates that the charge
is equal to zero. The name of any copper
compound must include the charge on the
copper cation.
9. a. Aluminum is a metal and chlorine is a
nonmetal, so aluminum chloride has
ionic bonding and conducts electricity in
solution only.
b. Oxygen is made up only of nonmetal atoms
and is a gas, so it has molecular covalent
bonding and does not conduct electricity.
c. Silver (I) hydroxide has ionic bonding and
conducts electricity in solution only.
d. Platinum is a metal element, so it has
metallic bonding and conducts electricity.
10.Possible answer: You can determine the charge
on a transition metal ion by the formula of its
salt. The total charge of the ionic compound
must be zero, so the positive charge on the
metal ion is the sum of the negative charges on
the anions divided by the number of metal ions
in the formula.
11.A material that does not dissolve in water and
does not conduct electricity is held together
by network covalent bonds or molecular
covalent bonds. Although some materials with
molecular covalent bonds dissolve in water,
others do not.
12.One element can be changed into another
only by changing the number of protons in
the nuclei of its atoms. This process requires
enormous amounts of energy.
Living By Chemistry Solutions Manual
© 2012 W. H. Freeman and Company/BFW
4/16/12 3:32:06 PM