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Chapter Review
The properties of compounds depend on their
atoms and chemical bonds.
CONTENT REVIEW
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KEY CONCEPTS SUMMARY
1
Elements combine to form compounds.
chemical formula p. 171
subscript p. 171
• Compounds have different properties from the
elements that made them.
• Atoms combine in predictable numbers.
+
calcium (Ca)
2
+
chlorine (Cl2)
=
calcium chloride
(CaCl2)
Chemical bonds between atoms involve electrons.
Atoms can transfer electrons.
Atoms can share electrons.
Chemical bonds give all materials their structure.
ionic bond
3
=
Chemical bonds hold compounds together.
•
•
•
•
• Metals have unique bonds.
• Ionic and covalent bonds give compounds certain properties.
• Bonds can make the same element look different.
190 Unit 2: Chemical Interactions
VOCABULARY
ionic bond p. 176
covalent bond p. 178
molecule p. 179
polar covalent bond
p. 179
covalent bond
Substances’ properties depend on their bonds.
copper
VOCABULARY
diamond fragment
graphite fragment
VOCABULARY
metallic bond p. 184
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Reviewing Vocabulary
Copy and complete the table below. Under
each bond type, describe
• how electrons are distributed
• how the compound is structured
• one of the properties of the compound
containing this type of bond
Some of the table has been filled out for you.
Ionic Bonds
Covalent Bonds
Metallic Bonds
1.
shared electron
pair
2.
3.
4.
close-packed
atoms in sea
of electrons
have high
melting points
5.
6.
Reviewing Key Concepts
Multiple Choice Choose the letter of the
best answer.
7. Most substances are
a. elements
c. metals
b. compounds
d. nonmetals
8. All compounds are made of
a. atoms of two or more elements
b. two or more atoms of the same element
c. atoms arranged in a crystal
d. atoms joined by covalent bonds
9. The chemical formula for a compound having
one barium (Ba) ion and two chloride (Cl)
ions is
a. BCl
c. BaCl2
b. BaCl
d. Ba2Cl2
11. The compound KBr has the name
a. potassium bromide
b. potassium bromine
c. bromide potassium
d. bromine potassium
12. An atom becomes a positive ion when it
a. is attracted to all nearby atoms
b. gains an electron from another atom
c. loses an electron to another atom
d. shares an electron with another atom
13. A polar covalent bond forms when two atoms
a. share one electron equally
b. share two electrons equally
c. share one electron unequally
d. share two electrons unequally
14. Metallic bonds make many metals
a. poor conductors of heat
b. liquid at room temperature
c. difficult to shape
d. good conductors of electricity
15. Three forms of carbon are
a. diamond, graphite, and salt
b. diamond, graphite, and fullerene
c. graphite, salt, and carbonate
d. diamond, salt, and fullerene
Short Answer Write a short answer to
each question.
16. Why does a mixture of sodium chloride and
water conduct electricity but a sodium chloride
crystal does not?
17. Describe what makes diamond and graphite,
two forms of the element carbon, so different.
10. The 4 in the chemical formula CH4 means
there are
a. four carbon atoms to one hydrogen atom
b. four carbon and four hydrogen atoms
c. four hydrogen atoms to one carbon atom
d. four total carbon CH combinations
Chapter 6: Chemical Bonds and Compounds 191
Page 3 of 4
Use the chemical formulas below and a
periodic table to answer the next three
questions.
Thinking Critically
N
H
H
H
Use the illustration above to answer the next
two questions.
18. IDENTIFY Write the chemical formula for the
molecule pictured above.
19. ANALYZE The nitrogen atom has a far greater
attraction for electrons than hydrogen atoms.
Copy the molecule pictured above and indicate
which parts of the molecule have a slightly
positive charge and which parts have a slightly
negative charge.
20. PREDICT The chemical formula for calcium
chloride is CaCl2. What would you predict the
formula for magnesium chloride to be? [Hint:
Find magnesium on the periodic table.]
21. INFER When scientists make artificial diamonds,
they sometimes subject graphite to very high
temperatures and pressures. What do you
think happens to change the graphite into
diamond?
22. SYNTHESIZE Why would seawater be a better
conductor of electricity than river water?
23. ANALYZE How does the nature of the metallic
bond explain the observation that most metals
can be drawn into a wire?
24. EVALUATE Do you think the types of bonds
you’ve studied occur on the planet Mars?
Explain.
25. INFER Why don’t we use the term ionic
molecule?
192 Unit 2: Chemical Interactions
I.
II.
III.
IV.
Compound
K2SO4
CF4
C4H10
KCl
26. APPLY Name compound IV. Does this
compound have ionic or covalent bonds?
27. ANALYZE Name the elements in each
compound. Tell how many atoms are in
each compound.
28. CALCULATE Express the ratio of atoms in
compounds II, III, and IV. For compound I,
express all three ratios.
29. APPLY By 1800 Alessandro Volta had made the
first electric battery. He placed pieces of cardboard soaked in saltwater in between alternating zinc and silver discs. What properties of
the metals and the saltwater made them good
materials for a battery?
30. PREDICT What is the maximum number of
covalent bonds that a hydrogen atom can
form? Explain your answer.
31. DRAW CONCLUSIONS Look at the photograph
on pages 166–167 again. Can you now recognize any similarities between how the skydivers
stay together and how atoms stay together?
32. APPLY Phosphorus can be a strange element.
Pure phosphorus is sometimes white, black,
or red. What can account for the differences
in appearance?
If you need to create graphs or other visuals
for your project, be sure you have graph paper,
poster board, markers, or other supplies.
Page 4 of 4
For practice on your
state test, go to . . .
Standardized Test Practice
TEST PRACTICE
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Interpreting Tables
The table below lists some of the characteristics of substances that contain
different types of bonds. Use the table to answer the questions.
Bond Type
Usually Forms
Between
Electrons
Properties
Examples
Ionic
an atom of a metal and
an atom of a nonmetal
transferred between
atoms
BaS, BaBr2,
Ca3N2, LiCl, ZnO
Covalent
atoms of nonmetallic
elements
shared between atoms
but often not equally
Metallic
atoms of metallic
elements
freely moving about
the atoms
• high melting points
• conducts electricity
when in water
• low melting points
• does not conduct
electricity
• high melting points
• conducts electricity
at all times
• easily shaped
1. Which of these compounds would you expect to
have the highest melting point?
a. C2H6
c. AsCl3
b. Cl2
d. BaBr2
2. Which substance is likely to be easily shaped?
a. BaBr2
c. Na
b. LiCl
d. C
3. In the compound LiCl, electrons are
a. shared equally
b. shared but not equally
c. transferred between atoms to form ions
d. freely moving among the atoms
Extended Response
Answer the next two questions in detail.
Include some of the terms from the list in the box.
Underline each term you use in your answer.
7. Compare how electrons are involved in making the
three main types of bonds: ionic, covalent, and
metallic.
C2H6, C, Cl2, H2,
AsCl3
Ca, Fe, Na, Cu,
Zn
4. Which of the following is an ionic compound?
a. C2H6
c. AsCl3
b. Cl2
d. ZnO
5. Which of the following compounds has a low
melting point?
a. Cl2
c. Cu
b. ZnO
d. BaBr2
6. A solid mass of which substance would conduct
electricity?
a. Ca3N2
c. Cu
b. LiCl
d. AsCl3
share electron
freely moving electrons
compound
transfer electron
charge
chemical formula
8. Just about 100 elements occur naturally. There are,
however, millions of different materials. How can
so few basic substances make so many different
materials?
Chapter 6: Chemical Bonds and Compounds 193