CH 010

Chapter 10 The Shapes of Molecules
Student: ______________________________________________________________________
1. In neutral molecules, how many bonds are commonly formed by nitrogen? And how many
by oxygen?
A. 5 and 6
B. 4 and 2
C. 3 and 6
D. 4 and 6
E. 3 and 2
2. Which one of the following Lewis structures is definitely incorrect?

A. BF3
B. XeO3
C. N2
D. AlCl4¯
E. NH4+
F.
A. NO
B. HCN
C. NO2¯
D. SO32¯
E. PCl5
A. NO2
B. BeCl2
C. CO32¯
D. CH4
E. SO2
5. Select the best Lewis structure for ClCN.
A.
B.
C.
D.
E.
6. Hydrazine, N2H4, is a good reducing agent that has been used as a component in rocket
fuels. Select its Lewis structure.
A.
B.
C.
D.
E. None of these choices is correct.
7. Select the correct Lewis structure for nitrogen trifluoride, NF3.
A.
B.
C.
D.
E.
8. Select the correct Lewis structure for NOCl, a reactive material used as an ionizing solvent.
A.
B.
C.
D.
9. Oxygen difluoride is a powerful oxidizing and fluorinating agent. Select its Lewis
structure.
A.
B.
C.
D.
10. Select the best Lewis structure for P2I4.
A.
B.
C.
D.
E. None of these structures is suitable for P2I4.
11. Thionyl chloride is used as an oxidizing and chlorinating agent in organic chemistry. Select
the best Lewis structure for SOCl2.
A.
B.
C.
D.
E. None of these structures is suitable for SOCl2.
12. Select the correct Lewis structure for TeBr2.
A.
B.
C.
D.
E.
13. How many electron pairs are shared between the carbon atoms in C2H4?
A. 5
B. 4
C. 3
D. 2
E. 1
14. In carbon disulfide, how many lone pairs of electrons are on each sulfur atom?
A. 0
B. 1
C. 2
D. 3
E. 4
15. Which one of the following molecules contains a double bond?
A. N2
B. PCl5
C. CH2O
D. C2H2
E. I2
16. In which one of the following molecules are all the bonds single?
A. O3
B. POCl3
C. CO
D. COCl2
E. N2H4
17. In which one of the following is the best Lewis structure a resonance structure?
A. CO2 (C = central atom)
B. ClO3¯ (Cl = central atom)
C. COCl2 (C = central atom)
D. NO2+ (N = central atom)
E. HCN (C = central atom)
18. In which one of the following is the best Lewis structure a resonance structure?
A. SO3
B. BF3
C. I3¯
D. SCO (C = central atom)
E. SO32¯
19. In the nitrate ion (NO3¯), nitrogen and oxygen are held together by
A. ionic interactions.
B. covalent bonds.
C. dative bonds.
D. electronegativity.
E. network bonds.
20. How many resonance structures are possible for NO3¯?

A. 1
B. 2
C. 3
D. 4
E. 5
21. In which one of the following species is the best Lewis structure a resonance structure?
A. NH3
B. CO2
C. SF6
D. O2
E. CO32¯
22. The best Lewis structure for sulfuric acid has zero formal charges, sulfur as the central
atom, and no bonds between S and H. How many single and double bonds, respectively, are
there in this Lewis structure?
A. 2 single, 4 double
B. 4 single, 2 double
C. 4 single, no double
D. 6 single, no double
E. 5 single, 1 double
23. Select the Lewis structure in which formal charges are minimized for the periodate anion,
IO4¯.
A.
B.
C.
D.
E.
24. Phosphoryl iodide is used in the preparation of organophosphorus derivatives and
phosphate esters. Select the Lewis structure for POI3 which minimizes formal charges.
A.
B.
C.
D.
E.
25. Select the Lewis structure for XeO2F2 which correctly minimizes formal charges.
A.
B.
C.
D.
E.
26. In the following Lewis structure for ClO3F, chlorine has a formal charge of ____ and an
oxidation number of ____.
A. 7, 7
B. 7, -1
C. 1, 1
D. 1, -1
E. 1, 7
27. In the following Lewis structure for phosphate, phosphorus has a formal charge of ____ and
an oxidation number of ____.
A. 0, -3
B. 0, 5
C. 5, -3
D. 5, 5
E. 3, 5
28. In which of the following does the nitrogen atom have a formal charge of -1?
A.
B.
C.
D.
E.
29. The formal charges on Cl and O in the structure shown for the ClO¯ ion are, respectively:
A. 0 and -1
B. -1 and 0
C. 1 and -2
D. -2 and 1
30. In which one of the following structures does the central atom have a formal charge of +2?
A. SF6
B. SO42¯
C. O3
D. BeCl2
E. AlCl4¯
31. The formal charge on Cl in the structure shown for the perchlorate ion is:
A. -2
B. -1
C. 0
D. +1
E. +2
32. In the COCl2 molecule, carbon is the central atom. Based on the best Lewis structure for
COCl2, what is the formal charge on carbon?
A. 0
B. +1
C. -1
D. +2
E. -2
33. In which one of the following species is the central atom (the first atom in the formula) an
exception to the octet rule?
A. NH3
B. NH4+
C. I2
D. BH4¯
E. SF6
34. In which one of the following species is the central atom (the first atom in the formula)
likely to violate the octet rule?
A. BF4¯
B. XeO3
C. SiCl4
D. NH3
E. CH2Cl2
35. Which of the following atoms can expand its valence shell when bonding?
A. N
B. C
C. O
D. P
E. Al
36. According to VSEPR theory, a molecule with the general formula AX2 will have a ___
molecular shape.
A. linear
B. bent
C. trigonal planar
D. tetrahedral
E. triangular
37. According to VSEPR theory, a molecule with the general formula AX3 will have a ______
molecular shape.
A. linear
B. bent
C. trigonal planar
D. tetrahedral
E. trigonal pyramidal
molecular shape.
A. bent
B. trigonal planar
C. trigonal pyramidal
D. square planar
E. tetrahedral
molecular shape.
A. tetrahedral
B. trigonal planar
D. trigonal bipyramidal
E. see-saw
40. Considering all the bonds in a molecule with trigonal bipyramidal geometry, what are the
bond angles present?
A. 120° only
B. 90° only
C. 180° only
D. 60° and 90° only
E. 90°, 120° and 180°
41. How many faces and how many vertexes (corners), respectively, are there in a trigonal
bipyramid?
A. 4 and 4
B. 5 and 5
C. 5 and 6
D. 6 and 5
E. 6 and 8
molecular shape.
A. tetrahedral
B. trigonal planar
C. trigonal bipyramidal
D. hexagonal
E. octahedral
43. According to VSEPR theory, a molecule with the general formula AX2E will have a
______ molecular shape.
A. bent
B. see-saw
C. trigonal planar
D. T-shaped
44. According to VSEPR theory, a molecule with the general formula AX2E2 will have a _____
molecular shape.
A. linear
B. bent
C. trigonal planar
D. tetrahedral
E. see-saw
molecular shape.
A. bent
B. linear
C. trigonal planar
D. T-shaped
46. According to VSEPR theory, a molecule with the general formula AX3E will have a _____
molecular shape.
A. bent
B. trigonal planar
D. tetrahedral
E. triangular
molecular shape.
A. trigonal pyramidal
B. trigonal bipyramidal
C. trigonal planar
D. T-shaped
E. see-saw
48. According to VSEPR theory, a molecule with the general formula AX4E will have a _____
molecular shape.
A. bent
B. see-saw
C. trigonal planar
D. T-shaped
E. square planar
molecular shape.
A. tetrahedral
B. square pyramidal
C. square planar
D. octahedral
E. see-saw
50. According to VSEPR theory, a molecule with the general formula AX5E will have a
______ molecular shape.
A. tetrahedral
C. square pyramidal
D. octahedral
E. see-saw
51. What is the molecular shape of N2O as predicted by the VSEPR theory?
B. trigonal planar
C. angular
D. bent
E. linear
52. What is the molecular shape of the thiocyanate anion, SCN¯, as predicted by the VSEPR
theory? (Carbon is the central atom.)
A. linear
B. bent
C. angular
D. trigonal
53. What is the molecular shape of ClCN as predicted by the VSEPR theory? (Carbon is the
central atom.)
A. linear
B. bent
C. angular
D. trigonal
54. What is the molecular shape of BeH2 as predicted by the VSEPR theory?
A. linear
B. bent
C. angular
D. trigonal
55. What is the molecular shape of NOCl as predicted by the VSEPR theory?
A. linear
B. trigonal planar
C. bent
D. tetrahedral
56. What is the molecular shape of BCl3 as predicted by the VSEPR theory?
A. linear
B. trigonal planar
C. bent
D. tetrahedral
57. What is the molecular shape of NO2¯ as predicted by the VSEPR theory?
A. linear
B. trigonal planar
C. bent
D. tetrahedral
E. resonant
58. What is the molecular symmetry around the carbons in CCl2CH2 as predicted by the
VSEPR theory?
A. linear
B. trigonal planar
C. V-shaped
D. tetrahedral
59. What is the molecular shape of ClO3F as predicted by the VSEPR theory?
B. square planar
C. square pyramidal
D. tetrahedral
E. octahedral
60. What is the molecular shape of HOF as predicted by the VSEPR theory?
B. trigonal
C. tetrahedral
D. linear
E. bent
61. What is the molecular shape of NH2Cl as predicted by the VSEPR theory?
B. tetrahedral
C. T-shaped
D. see-saw
E. trigonal planar
62. What is the molecular shape of XeO2F2 as predicted by the VSEPR theory?
A. square planar
B. tetrahedral
C. square pyramidal
D. see-saw
E. octahedral
63. What is the molecular shape of ClF2¯ as predicted by the VSEPR theory?
A. linear
B. bent
C. see-saw
D. T-shaped
E. L-shaped
64. What is the molecular shape of SCl3F as predicted by the VSEPR theory?
A. linear
B. bent
C. see-saw
D. T-shaped
65. What is the molecular shape of SiF62¯ as predicted by the VSEPR theory?
A. trigonal bipyramidal
B. hexagonal
C. tetrahedral
D. see-saw
E. octahedral
66. What is the molecular shape of ClF4¯ as predicted by the VSEPR theory?
A. square pyramidal
B. square planar
C. see-saw
D. octahedral
E. tetrahedral
67. Which one of the following molecules and ions will have a planar geometry?
A. PCl3
B. BF4¯
C. XeF4
D. BrF5
E. H3O+
68. Use VSEPR theory to decide which one of the following ions and molecules is likely to be
planar. (The central atom is always first in the formula.)
A. BrF3
B. H3O+
C. PCl3
D. SO42¯
E. SF4
69. Use VSEPR theory to decide which one of the following molecules and ions will have a
trigonal pyramidal geometry. (The central atom is always first in the formula.)
A. PCl3
B. BF3
C. SO3
D. BrF3
E. CO32¯
70. Use VSEPR theory to predict the electron group arrangement around iodine, the central
atom in the ion IF2¯.
A. octahedral
C. tetrahedral
D. trigonal planar
E. bent
71. Use VSEPR theory to decide which one of the following molecules and ions will definitely
have at least one 90° bond angle in it. (In each case except water, the central atom is the
first one in the formula.)
A. AlCl4¯
B. NH3
C. PCl5
D. CO2
E. H2O
72. Predict the ideal bond angles in GeCl4 using the molecular shape given by the VSEPR
theory.
A. 90°
B. 109°
C. 120°
D. 180°
E. < 90°
73. Predict the ideal bond angles in AsCl3 using the molecular shape given by the VSEPR
theory.
A. 90°
B. 109°
C. 120°
D. 180°
E. between 110 and 120°
74. Predict the ideal bond angles in FNO using the molecular shape given by the VSEPR
theory.
A. 90°
B. 109°
C. 120°
D. 180°
75. Predict the ideal bond angles around nitrogen in N2F2 using the molecular shape given by
the VSEPR theory. (The two N atoms are the central atoms.)
A. 90°
B. 109°
C. 120°
D. 180°
76. Predict the ideal bond angles around carbon in C2I2 using the molecular shape given by the
VSEPR theory.
A. 90°
B. 109°
C. 120°
D. 180°
77. Predict the ideal bond angles in IF2¯ using the molecular shape given by the VSEPR
theory.
A. 60°
B. 90°
C. 109°
D. 120°
E. 180°
78. Predict the actual bond angle in SeCl2 using the VSEPR theory.
A. more than 120°
B. between 109° and 120°
C. between 90° and 109°
D. exactly 90°
E. less than 90°
79. Predict the smallest actual bond angle in BrF3 using the VSEPR theory.
A. more than 120°
B. exactly 120°
D. between 90° and 109°
E. less than 90°
80. Predict the actual bond angles in SF3+ using the VSEPR theory.
A. more than 120°
B. exactly 120°
D. between 90° and 109°
E. less than 90°
81. List all possible molecular geometries (shapes) for a nonpolar molecule with the formula
AX4.
A. tetrahedral
B. seesaw
C. square planar
D. either tetrahedral or square planar
E. All of these choices are possible.
82. Which of the following molecules has a net dipole moment?

A. BeCl2
B. SF2
C. KrF2
D. CO2
E. CCl4
83. Which of the following has no net dipole moment?

A. N2O
B. NF3
C. H2Se
D. TeO3
E. CH3Cl
84. Which one of the following molecules has a zero dipole moment?
A. SO2
B. HCl
C. CS2
D. CO
E. Cl2O
85. Which one of the following molecules does not have a dipole moment?
A. CS2
B. H2S
C. CH2Cl2
D. PH3
E. CH2O
86. Draw Lewis structures, showing all valence electrons, for:
a. N
b. Br¯
c. O2
d. SO42¯
87. Draw Lewis structures, showing all valence electrons, for the following species:
a. S2¯
b. CO
c. SO2
d. CH3OH
88. Draw Lewis structures which obey the octet rule, for the following atoms, molecules and
ions, showing all valence electrons. Central atoms are shown in bold.
a. NH3
b. O3 (Hint: O3 is not cyclic)
c. HCN
d. SO3
89. For the chlorate ion, ClO3¯, draw two different valid Lewis structures, as follows:
a. a structure in which the octet rule is obeyed.
b. a structure in which formal charges are minimized.
90. Name and outline the concept which is introduced when more than one valid Lewis
structure can be drawn for a given molecule or ion. Use appropriate diagrams of the formate
ion (HCO2¯, carbon is the central atom) to illustrate.
91. Draw all important resonance structures of the nitrate ion, NO3¯.
92. Using SO2 as an example, describe the sort of experimental data which might suggest that
no single Lewis structure is an accurate representation of its bonding.
93. List the three important ways in which molecules can violate the octet rule, and in each case
draw one Lewis structure of your choice as an example.
94. The Lewis structure of formaldehyde, CH2O, is shown. Use VSEPR theory to predict the
molecular geometry and the H-C-H bond angle. Outline your reasoning.
95. What is the shape of the PF3 molecule? Explain your answer, using VSEPR theory.
96. Draw the Lewis structure of XeF4. Use this structure, in conjunction with VSEPR theory, to
predict the shape of this molecule. Outline your reasoning.
97. a. Draw and name three molecular shapes for molecules having the VSEPR formulas AX3,
AX3E and AX3E2, respectively.
b. If the three X groups in the above formulas are identical, which of the three shapes would
result in a molecule with a dipole moment?
98. Explain what is meant by "dipole moment", and give an example of a molecule which has
polar bonds but which does not itself have a dipole moment.
99. All possible resonance structures contribute equally to the resonance hybrid.
Difficulty: M
True False
100. When resonance occurs, the bond lengths in a molecule fluctuate rapidly.
Difficulty: E
True False
101. In a Lewis structure for a molecule or ion, the sum of the formal charges on the atoms is
equal to the charge on the molecule or ion.
Difficulty: E
True False
102. In formaldehyde, CH2O, both the formal charge and the oxidation number of carbon are
zero.
Difficulty: M
True False
103. Boron never achieves an octet in any of its compounds.

Difficulty: M
True False
104. The Lewis structure of NO2 violates the octet rule.

Difficulty: M
True False
105. Bond angles of 180° only occur around atoms which display linear molecular geometry.
Difficulty: M
True False
106. In order for a non-cyclic triatomic molecule to be bent, VSEPR theory requires that there
must be two lone pairs on the central atom.
Difficulty: M
True False
107. According to VSEPR theory, a molecule with the general formula AX3E2 (where E
represents a lone pair on A) will be trigonal planar.
Difficulty: M
True False
108. The molecule AX2, where A and X are different elements, will have a dipole moment if the
molecule is bent.
Difficulty: E
True False
109. A molecule which contains polar bonds will always have a dipole moment.
Difficulty: H
True False
Chapter 10 The Shapes of Molecules Key
1. (p. 379) E
2. (p. 380) C
3. (p. 380) B
4. (p. 380) E
5. (p. 380) A
6. (p. 380) C
7. (p. 380) A
8. (p. 380) B
9. (p. 380) D
10. (p. 380) A
11. (p. 380) B
12. (p. 380) E
13. (p. 381) D
14. (p. 381) C
15. (p. 381) C
16. (p. 379) E
17. (p. 381) B
18. (p. 381) E
19. (p. 383) B
20. (p. 383) C
21. (p. 381) E
22. (p. 383) B
23. (p. 383) D
24. (p. 383) C
25. (p. 383) B
26. (p. 384) E
27. (p. 384) B
28. (p. 383) C
29. (p. 383) A

30. (p. 383) B
31. (p. 383) D
32. (p. 383) A
33. (p. 385) E
34. (p. 385) B
35. (p. 385) D
36. (p. 394) A
37. (p. 394) C
38. (p. 394) E
39. (p. 394) D
40. (p. 394) E
41. (p. 394) D
42. (p. 394) E
43. (p. 394) A
44. (p. 394) B
45. (p. 394) B
46. (p. 394) C
47. (p. 394) D
48. (p. 394) B
49. (p. 394) C
50. (p. 394) C
51. (p. 395) E
52. (p. 395) A
53. (p. 395) A
54. (p. 395) A
55. (p. 395) C
56. (p. 395) B
57. (p. 395) C
58. (p. 395) B
59. (p. 395) D
60. (p. 395) E

61. (p. 395) A
62. (p. 396) D
63. (p. 396) A
64. (p. 396) C
65. (p. 396) E
66. (p. 395) B
67. (p. 395, 396) C
68. (p. 395, 396) A
69. (p. 395, 396) A
70. (p. 396) B
71. (p. 395) C
72. (p. 395) B
73. (p. 395) B
74. (p. 395) C
75. (p. 395) C
76. (p. 395) D
77. (p. 396) E
78. (p. 395) C
79. (p. 396) E
80. (p. 396) D
81. (p. 395) D
82. (p. 400) B
83. (p. 400) D
84. (p. 400) C
85. (p. 400) A

86. (p. 378) a.
b.
c.
d.
Difficulty: E
87. (p. 378) a.
b.
c.
d.
Difficulty: M
88. (p. 378) a.
b.
c.
d.
Difficulty: M
89. (p. 383) a.
b.
Difficulty: M
90. (p. 383) The concept is resonance. In this situation no single Lewis structure can adequately represent the bonding in a
molecule. An average of the different Lewis structures is a better representation of the bonding than any single structure.
The two important resonance structures are shown below.
Difficulty: H
91. (p. 383)

Difficulty: M
92. (p. 381) In the SO2 molecule, the two sulfur-oxygen bonds would be identical in length and strength, and these values
would be intermediate between those of sulfur-oxygen single and double bonds. A single Lewis structure would show two
different types of bond in the molecule, one single and one double.
Difficulty: M
93. (p. 384) Electron-deficient molecules have fewer than 8 electrons in the valence shells of atoms, e.g., boron in BF3. Odd-
electron molecules cannot obey the octet rule. Examples are NO, NO2 and ClO2. Atoms from period 3 and beyond can
expand their valence shells to exceed the octet count. Example: SF6.
Difficulty: M
94. (p. 395) There are three electron groups around the central atom, carbon. These are a double bond and two single bonds.
The molecule is thus of the AX3 type, and its geometry will be trigonal planar. The bond angles will be 120°.
Difficulty: M
95. (p. 395) The Lewis structure has a lone pair on the phosphorus atom, and the VSEPR formula is thus AX3E. There are four
electron groups, giving a tetrahedral electron group arrangement. The molecular shape is trigonal pyramidal.
Difficulty: M
96. (p. 396) The Lewis structure is shown below. The VSEPR formula is AX4E2, and the electron group arrangement is
therefore octahedral. The lone pairs will lie at opposite vertices, resulting in a square planar molecular geometry.
Difficulty: M
97. (p. 394) a. The three structures and their molecular shapes are shown below.
b. The trigonal pyramidal and T-shaped molecules will have dipole moments.
Difficulty: M
98. (p. 399) A dipole moment arises in a molecule when the "centers of gravity" of the positive and negative charges do not
coincide. There is thus a separation of charge. The dipole moment is the product of this charge and the distance of
separation. Carbon dioxide has two polar carbon-oxygen bonds. However, because the molecule is linear, the two bond
dipoles are exactly opposite in direction, and they cancel each other out. The CO2 molecule has no dipole moment.
Difficulty: E
99. (p. 383) FALSE
100. (p. 382) FALSE
101. (p. 383) TRUE
102. (p. 384) FALSE
103. (p. 385) FALSE
104. (p. 385) TRUE
105. (p. 396) FALSE
106. (p. 395) FALSE
107. (p. 396) FALSE
108. (p. 400) TRUE
109. (p. 400) FALSE

CH 010

Uploaded by

Copyright:

Available Formats

CH 010

Uploaded by

Document Information

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

CH 010

Uploaded by

Copyright:

Available Formats

Chapter 10 The Shapes of Molecules

2. Which one of the following Lewis structures is definitely incorrect?

5. Select the best Lewis structure for ClCN.

E. None of these choices is correct.

7. Select the correct Lewis structure for nitrogen trifluoride, NF3.

20. How many resonance structures are possible for NO3¯?

82. Which of the following molecules has a net dipole moment?

83. Which of the following has no net dipole moment?

103. Boron never achieves an octet in any of its compounds.

104. The Lewis structure of NO2 violates the octet rule.

10. (p. 380) A

11. (p. 380) B

12. (p. 380) E

13. (p. 381) D

14. (p. 381) C

15. (p. 381) C

16. (p. 379) E

17. (p. 381) B

18. (p. 381) E

19. (p. 383) B

20. (p. 383) C

21. (p. 381) E

22. (p. 383) B

23. (p. 383) D

24. (p. 383) C

25. (p. 383) B

26. (p. 384) E

27. (p. 384) B

28. (p. 383) C

29. (p. 383) A

31. (p. 383) D

32. (p. 383) A

33. (p. 385) E

34. (p. 385) B

35. (p. 385) D

36. (p. 394) A

37. (p. 394) C

38. (p. 394) E

39. (p. 394) D

40. (p. 394) E

41. (p. 394) D

42. (p. 394) E

43. (p. 394) A

44. (p. 394) B

45. (p. 394) B

46. (p. 394) C

47. (p. 394) D

48. (p. 394) B

49. (p. 394) C

50. (p. 394) C

51. (p. 395) E

52. (p. 395) A

53. (p. 395) A

54. (p. 395) A

55. (p. 395) C

56. (p. 395) B

57. (p. 395) C

58. (p. 395) B

59. (p. 395) D