Chapter 7
Matching
Match each item with the correct statement below.
a. halide ion
e. valence electron
b. octet rule
f. coordination number
c. ionic bond
g. metallic bond
d. electron dot structure
____
____
____
____
____
____
____
1.
2.
3.
4.
5.
6.
7.
an electron in the highest occupied energy level of an atom
Atoms react so as to acquire the stable electron structure of a noble gas.
a depiction of valence electrons around the symbol of an element
an anion of chlorine or other halogen
the force of attraction binding oppositely charged ions together
the attraction of valence electrons for metal ions
the number of ions of opposite charge surrounding each ion in a crystal
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
____
____
____
____
____
____
____
____
8. How many valence electrons are in an atom of phosphorus?
a. 2
c. 4
b. 3
d. 5
9. How many valence electrons are in an atom of magnesium?
a. 2
c. 4
b. 3
d. 5
10. How many valence electrons does a helium atom have?
a. 2
c. 4
b. 3
d. 5
11. How many valence electrons are in a silicon atom?
a. 2
c. 6
b. 4
d. 8
12. What is the name given to the electrons in the highest occupied energy level of an atom?
a. orbital electrons
c. anions
b. valence electrons
d. cations
13. How does calcium obey the octet rule when reacting to form compounds?
a. It gains electrons.
b. It gives up electrons.
c. It does not change its number of electrons.
d. Calcium does not obey the octet rule.
14. What is the maximum charge an ion is likely to have?
a. 2
c. 4
b. 3
d. 5
15. What is the electron configuration of the calcium ion?
a. 1s 2s 2p 3s 3p
c. 1s 2s 2p 3s 3p 4s
b. 1s 2s 2p 3s 3p 4s
d. 1s 2s 2p 3s
____ 16. What is the electron configuration of the gallium ion?
a. 1s 2s 2p 3s 3p
c. 1s 2s 2p 3s 3p 4s 4p
b. 1s 2s 2p 3s 3p 4s
d. 1s 2s 2p 3s 3p 3d
____ 17. What is the charge on the strontium ion?
a. 2–
c. 1
b. 1–
d. 2
____ 18. The octet rule states that, in chemical compounds, atoms tend to have ____.
a. the electron configuration of a noble gas
b. more protons than electrons
c. eight electrons in their principal energy level
d. more electrons than protons
____ 19. How many electrons does silver have to give up in order to achieve a pseudo-noble-gas electron
configuration?
a. 1
c. 3
b. 2
d. 4
____ 20. How many electrons does barium have to give up to achieve a noble-gas electron configuration?
a. 1
c. 3
b. 2
d. 4
____ 21. What is the formula of the ion formed when potassium achieves noble-gas electron configuration?
a. K
c. K
b. K
d. K
____ 22. Which of the following ions has a pseudo-noble-gas electron configuration?
a. Fe
c. Cu
b. Mn
d. Ni
____ 23. Which of the following elements does NOT form an ion with a charge of 1 ?
a. fluorine
c. potassium
b. hydrogen
d. sodium
____ 24. What is the formula of the ion formed when tin achieves a stable electron configuration?
a. Sn
c. Sn
b. Sn
d. Sn
____ 25. What is the formula of the ion formed when cadmium achieves a pseudo-noble-gas electron configuration?
a. Cd
c. Cd
b. Cd
d. Cd
____ 26. Which of the following is a pseudo-noble-gas electron configuration?
a. 1s 2s 2p 3s 3d
c. 1s 2s 2p 3s 3p 3d
b. 1s 2s 2p 3s 3p
d. 1s 2s 2p 3s 3d 4s
____ 27. How many electrons does nitrogen gain in order to achieve a noble-gas electron configuration?
a. 1
c. 3
b. 2
d. 4
____ 28. What is the formula of the ion formed when phosphorus achieves a noble-gas electron configuration?
a. P
c. P
b. P
d. P
____ 29. How does oxygen obey the octet rule when reacting to form compounds?
a. It gains electrons.
b. It gives up electrons.
c. It does not change its number of electrons.
d. Oxygen does not obey the octet rule.
____ 30. The electron configuration of a fluoride ion, F , is ____.
a. 1s 2s 2p
c. 1s 2s 2p 3s
b. the same as that of a neon atom
d. the same as that of a potassium ion
____ 31. What is the electron configuration of the oxide ion (O )?
a. 1s 2s 2p
c. 1s 2s
b. 1s 2s 2p
d. 1s 2s 2p
____ 32. What is the electron configuration of the iodide ion?
a. 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p
b. 1s 2s 2p 3s 3p 3d 4s 4p 4d
c. 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s
d. 1s 2s 2p 3s 3p 3d 4s 4p
____ 33. What is the charge on the cation in the ionic compound sodium sulfide?
a. 0
c. 2
b. 1
d. 3
____ 34. Which of the following occurs in an ionic bond?
a. Oppositely charged ions attract.
b. Two atoms share two electrons.
c. Two atoms share more than two electrons.
d. Like-charged ions attract.
____ 35. What is the net charge of the ionic compound calcium fluoride?
a. 2–
c. 0
b. 1–
d. 1
____ 36. A compound held together by ionic bonds is called a ____.
a. diatomic molecule
c. covalent molecule
b. polar compound
d. salt
____ 37. Which of the following is true about an ionic compound?
a. It is a salt.
c. It is composed of anions and cations.
b. It is held together by ionic bonds.
d. all of the above
____ 38. How many valence electrons are transferred from the nitrogen atom to potassium in the formation of the
compound potassium nitride?
a. 0
c. 2
b. 1
d. 3
____ 39. How many valence electrons are transferred from the calcium atom to iodine in the formation of the
compound calcium iodide?
a. 0
c. 2
b. 1
d. 3
____ 40. What is the formula unit of sodium nitride?
a. NaN
c. Na N
b. Na N
d. NaN
____ 41. What is the formula unit of aluminum oxide?
a. AlO
b. Al O
c. AlO
d. Al O
____ 42. What is the name of the ionic compound formed from lithium and bromine?
a. lithium bromine
b. lithium bromide
____ 43. What is the formula for sodium sulfate?
a. NaSO
b. Na SO
____ 44. What is the formula for potassium sulfide?
a. KS
b. K S
c. lithium bromium
d. lithium bromate
c. Na(SO )
d. Na (SO )
c. KS
d. K S
____ 45. Which of the following compounds has the formula KNO ?
a. potassium nitrate
c. potassium nitrite
b. potassium nitride
d. potassium nitrogen oxide
____ 46. Which of the following pairs of elements is most likely to form an ionic compound?
a. magnesium and fluorine
c. oxygen and chlorine
b. nitrogen and sulfur
d. sodium and aluminum
____ 47. Ionic compounds are normally in which physical state at room temperature?
a. solid
c. gas
b. liquid
d. plasma
____ 48. Which of the following is true about the melting temperature of potassium chloride?
a. The melting temperature is relatively high.
b. The melting temperature is variable and unpredictable.
c. The melting temperature is relatively low.
d. Potassium chloride does not melt.
____ 49. What does the term coordination number in ionic crystals refer to?
a. the total number of valence electrons in an atom
b. the number of oppositely charged ions surrounding a particular ion
c. the number of atoms in a particular formula unit
d. the number of like-charged ions surrounding a particular ion
____ 50. Under what conditions can potassium bromide conduct electricity?
a. only when melted
b. only when dissolved
c. only when it is in crystal form
d. only when melted or dissolved in water
____ 51. Which of the following is NOT a characteristic of most ionic compounds?
a. They are solids.
b. They have low melting points.
c. When melted, they conduct an electric current.
d. They are composed of metallic and nonmetallic elements.
____ 52. Which of the following particles are free to drift in metals?
a. protons
c. neutrons
b. electrons
d. cations
____ 53. What is the basis of a metallic bond?
a. the attraction of metal ions to mobile electrons
b. the attraction between neutral metal atoms
c. the neutralization of protons by electrons
d. the attraction of oppositely charged ions
____ 54. What characteristic of metals makes them good electrical conductors?
a. They have mobile valence electrons.
b. They have mobile protons.
c. They have mobile cations.
d. Their crystal structures can be rearranged easily.
____ 55. An ionic bond is a bond between ____.
a. a cation and an anion
c. the ions of two different metals
b. valence electrons and cations
d. the ions of two different nonmetals
____ 56. In a hexagonal close-packed crystal, every atom (except those on the surface) has ____ neighbors.
a. 6
c. 12
b. 8
d. 10
____ 57. Which metallic crystal structure has a coordination number of 8?
a. body-centered cubic
c. hexagonal close-packing
b. face-centered cubic
d. tetragonal
Short Answer
58. Give the electron configurations for boron and its ion.
59. Give the electron configurations for mercury and its 2 ion.
60. Give the electron configuration for calcium the ion.
61. Give the electron configuration for the lithium ion.
62. Give the electron configurations for iodine and its 1– ion.
63. What is the formula for the oxide ion?
64. Give the electron configuration for the chloride ion.
65. Give the electron configuration for the oxide ion.
66. Write the formula for the compound barium oxide.
67. Write the formula for the compound rubidium phosphide.
68. Write the formula for the compound boron chloride.
69. Write the electron configuration diagram that shows the transfer of electrons that takes place to form the
compound sodium fluoride. Include the electron configurations of the ions formed.
Numeric Response
70. How many valence electrons are in rubidium?
71. How many valence electrons are in bromine?
72. What is the charge of a particle having 9 protons and 10 electrons?
73. How many electrons does a gallium atom give up when it becomes an ion?
74. What is the coordination number of both ions in the cesium chloride crystal?
Essay
75. Explain the octet rule and give an example of how it is used.
76. Explain what a pseudo-noble-gas electron configuration is. Give examples of ions that have this type of
configuration.
77. Explain how atoms (ions) are held together in an ionic bond. Give an example of an ionic compound.
78. Why must each cation in an ionic solid be surrounded by anions?
79. Explain how a pure metal is held together. Include a definition of a metallic bond in your explanation.
80. Explain how scientists have used metallic bonding to account for many of the physical properties of metals,
such as electrical conductivity and malleability.
Chapter 7
Answer Section
MATCHING
1.
2.
3.
4.
5.
6.
7.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
E
B
D
A
C
G
F
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
L1
L1
L1
L1
L1
L1
L1
REF:
REF:
REF:
REF:
REF:
REF:
REF:
p. 187
p. 188
p. 188
p. 192
p. 194
p. 201
p. 198
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
7.1.1
7.1.2
7.1.4
7.1.4
7.2.1
7.2.1
7.2.2
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
L1
L1
L1
L1
L1
L1
L1
L2
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
p. 187
p. 188
p. 188
p. 188
p. 187
p. 188
p. 189
p. 188, p. 189
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
7.1.1
7.1.1
7.1.1
7.1.1
7.1.1
7.1.1
7.1.1
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
L2
L1
L2
L1
L1
L1
L1
L1
L2
L2
L2
L1
L1
L1
L1
L2
L2
L1
L1
L1
L1
L1
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
REF:
p. 190
p. 190
p. 188
p. 190
p. 190
p. 190
p. 190
p. 190
p. 190
p. 190
p. 190
p. 192
p. 192
p. 191
p. 192
p. 192
p. 192
p. 194
p. 194
p. 194
p. 194
p. 194
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
7.1.1
7.1.2
7.1.2
7.1.3
7.1.3
7.1.3
7.1.3
7.1.3
7.1.3
7.1.3
7.1.3
7.1.4
7.1.4
7.1.4
7.1.4
7.1.4
7.1.4
7.2.1
7.2.1
7.2.1
7.2.1
7.2.1
MULTIPLE CHOICE
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
OBJ:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
D
A
A
B
B
B
B
A
7.1.1
D
D
A
A
B
B
C
A
A
B
C
C
D
A
B
B
A
B
A
C
D
D
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
ANS:
ANS:
ANS:
ANS:
ANS:
OBJ:
ANS:
OBJ:
ANS:
OBJ:
ANS:
OBJ:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
OBJ:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
A
C
C
D
B
7.2.1
B
7.2.1
B
7.2.1
A
7.2.1
A
A
A
B
D
B
7.2.2
B
A
A
A
C
A
DIF:
DIF:
DIF:
DIF:
DIF:
L2
L2
L2
L2
L2
REF:
REF:
REF:
REF:
REF:
p. 194
p. 194
p. 195
p. 195
p. 192, p. 195
OBJ:
OBJ:
OBJ:
OBJ:
7.2.1
7.2.1
7.2.1
7.2.1
DIF: L2
REF: p. 192, p. 195
DIF: L2
REF: p. 192, p. 195
DIF: L2
REF: p. 192, p. 194
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
L3
L1
L1
L1
L1
L1
REF:
REF:
REF:
REF:
REF:
REF:
p. 194
p. 196
p. 196
p. 198
p. 198
p. 196, p. 198
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
7.2.1
7.2.2
7.2.2
7.2.2
7.2.2
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
L1
L1
L1
L1
L1
L1
REF:
REF:
REF:
REF:
REF:
REF:
p. 201
p. 201
p. 201
p. 201
p. 202
p. 202
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
7.3.1
7.3.1
7.3.1
7.2.1, 7.3.1
7.3.2
7.3.2
SHORT ANSWER
58. ANS:
B: 1s 2s 2p
B : 1s
DIF: L2
REF: p. 190
OBJ: 7.1.3
59. ANS:
Hg: 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 6s
Hg : 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d
DIF: L2
60. ANS:
1s 2s 2p 3s 3p
REF: p. 190
OBJ: 7.1.3
DIF: L2
61. ANS:
1s
REF: p. 190
OBJ: 7.1.3
DIF: L2
REF: p. 190
OBJ: 7.1.3
62. ANS:
I: 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p
I : 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p
DIF: L2
63. ANS:
O
REF: p. 192
OBJ: 7.1.4
DIF: L2
64. ANS:
1s 2s 2p 3s 3p
REF: p. 192
OBJ: 7.1.4
DIF: L2
65. ANS:
1s 2s 2p
REF: p. 192
OBJ: 7.1.4
DIF: L2
66. ANS:
BaO
REF: p. 192
OBJ: 7.1.4
DIF: L2
67. ANS:
Rb P
REF: p. 195
OBJ: 7.2.1
DIF: L2
68. ANS:
BCl
REF: p. 195
OBJ: 7.2.1
DIF: L2
69. ANS:
Na(1s 2s 2p 3s )
REF: p. 195
OBJ: 7.2.1
DIF: L3
F(1s 2s 2p )
Na (1s 2s 2p )
REF: p. 195
OBJ: 7.2.1
DIF: L1
71. ANS:
7
REF: p. 188
OBJ: 7.1.1
DIF: L1
72. ANS:
1
REF: p. 188
OBJ: 7.1.1
NUMERIC RESPONSE
70. ANS:
1
F (1s 2s 2p )
DIF: L1
73. ANS:
3
REF: p. 190
OBJ: 7.1.1
DIF: L2
74. ANS:
8
REF: p. 190
OBJ: 7.1.3
DIF: L2
REF: p. 198
OBJ: 7.2.2
ESSAY
75. ANS:
The electron configurations of the noble gases are extremely stable. The octet rule states that, in chemical
reactions, elements gain or lose electrons to achieve a noble gas configuration. This stable configuration is
called an octet because it consists of 8 valence electrons (s p ), 2 from the outermost s orbital and 6 from the
outermost p orbital. Oxygen has the electron configuration 1s 2s 2p . When oxygen reacts to form ionic
compounds, it completes its octet by gaining two electrons from the element it reacts with. These two
electrons add to the p orbital of oxygen, giving it the electron configuration (1s 2s 2p ) of neon.
DIF: L3
REF: p. 188
OBJ: 7.1.2
76. ANS:
A pseudo-noble-gas configuration has the form s p d . It has 18 electrons in the outer energy level and is a
relatively stable configuration. Examples of ions with this configuration are Ag , Cu , Cd , and Hg .
DIF: L3
REF: p. 190
OBJ: 7.1.3
77. ANS:
In an ionic bond, oppositely charged ions are held together by the electronic force of attraction that exists
between oppositely charged particles. In the ionic compound, anions and cations are present in a ratio that
causes the total charge on the compound to be zero. Sodium phosphide, Na P, has three sodium ions for each
phosphide ion. This ratio insures a zero total charge given the charges on the two individual ions (Na = 1 , P
= 3–).
DIF: L3
REF: p. 194
OBJ: 7.2.1
78. ANS:
In this arrangement, like-charged ions are shielded from each other and electronic repulsion is reduced. Also,
the force of attraction between oppositely charged ions is maximized. Each of these events contributes to a
lowering of energy and an increase in stability of the ionic compound.
DIF: L3
REF: p. 196
OBJ: 7.2.2
79. ANS:
A piece of pure metal, such as copper or iron, consists not of metal atoms, but of closely packed cations. The
cations are surrounded by mobile valence electrons that are free to drift from one part of the metal to another.
Metallic bonds result from the attraction between the free-floating valence electrons and the positively
charged metal ions.
DIF: L3
80. ANS:
REF: p. 201
OBJ: 7.3.1
Metallic bonds are the result of the attraction of free-floating valence electrons to positively charged metal
ions. An electric current is a flow of electrons. As electrons enter one end of a piece of metal, some of the
free-floating electrons leave the other end. Thus metals are good conductors of electricity. The cations in a
piece of metal are insulated from each other by the free electrons. Thus when the metal is struck, the cations
slide past each other easily. This makes the metal malleable and ductile.
DIF: L3
REF: p. 201, p. 202
OBJ: 7.3.1