Chapter 10: The Shapes of Molecules
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) A B) B C) C D) D E) E
3. Which one of the following Lewis structures is definitely incorrect?
A) NO
N
O
D) SO32–
S
O
O
O
2-
B) HCN
C
H
N
E) PCl5
P
Cl
Cl
Cl Cl
Cl
C) NO2–
N
O
O–
4. Which one of the following Lewis structures is definitely incorrect?
A) A B) B C) C D) D E) E
Chapter 10: The Shapes of Molecules
5. Select the best Lewis structure for ClCN.
A)
Cl C N
D)
Cl C N
B)
E)
Cl C N
C)
Cl C N
6. Hydrazine, N2H4, is a good reducing agent that has been used as a component in rocket
fuels. Select its Lewis structure.
A)
H N N H
H H
B)
N N HH
H H
C)
H N N H
H H
D)
H N N H
H
H
E) None of the above is correct.
Chapter 10: The Shapes of Molecules
7. Select the correct Lewis structure for nitrogen trifluoride, NF3.
A)
N
F
FF
B)
N
F
F
F
C)
N
F
FF
D)
N
F
FF
E)
N
F
FF
8. Select the correct Lewis structure for NOCl, a reactive material used as an ionizing
solvent.
A)
O N Cl
D)
O N Cl
B)
O N Cl
E) None of the above is correct.
C)
O N Cl
9. Oxygen difluoride is a powerful oxidizing and fluorinating agent. Select its Lewis
structure.
A)
F O F
D)
F O F
B)
F O F
E) None of the above is correct.
C)
F O F
Chapter 10: The Shapes of Molecules
10. Select the best Lewis structure for P2I4.
A)
P P
I I
II
B)
P P
I I
II
C)
P P
I I
II
D)
P P
I I
II
E) None of the above 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)
OS
Cl
Cl
B)
OS
Cl
Cl
C)
O S
Cl
Cl
D)
O S
Cl
Cl
E) None of the above structures is suitable for SOCl2.
Chapter 10: The Shapes of Molecules
12. Select the correct Lewis structure for TeBr2.
A)
Br
Te
Br
B)
Br
Te
Br
C)
Br
Te
Br
D)
Br
Te
Br
E)
Br
Te
Br
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
Chapter 10: The Shapes of Molecules
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? (central
atoms are bold)
A) CO2 B) ClO3– C) COCl2 D) NO2+ E) HCN
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. D) electronegativity.
B) covalent bonds. E) network bonds.
C) dative 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 D) 6 single, no double
B) 4 single, 2 double E) 5 single, 1 double
C) 4 single, no double
Chapter 10: The Shapes of Molecules
23. Select the Lewis structure in which formal charges are minimized for the periodate
anion, IO4–.
A)
I
O
O
O O
B)
I
O
O
O O
C)
I
O
O
O O
D)
I
O
O
O O
E)
I
O
O
O O
Chapter 10: The Shapes of Molecules
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)
P
I
I
O I
B)
P
I
I
O I
C)
P
I
I
O I
D)
P
I
I
O I
E)
P
I
I
O I
Chapter 10: The Shapes of Molecules
25. Select the Lewis structure for XeO2F2 which correctly minimizes formal charges.
A)
Xe
F
O
F O
B)
Xe
F
O
F O
C)
Xe
F
O
F O
D)
Xe
F
O
F O
E)
Xe
F
O
F O
26. In the following Lewis structure for ClO3F, chlorine has a formal charge of ____ and an
oxidation number of ____.
Cl
O
O
OF
A) 7, 7 B) 7, –1 C) 1, 1 D) 1, –1 E) 1, 7
Chapter 10: The Shapes of Molecules
27. In the following Lewis structure for phosphate, phosphorus has a formal charge of ____
and an oxidation number of ____.
P
O
O
O O
3-
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)
N3-
B)
N
H
H
H
C)
C
O
N–
D)
C
O
N–
E)
C
O
N–
Chapter 10: The Shapes of Molecules
29. The formal charges on Cl and O in the structure shown for the ClO– ion are, respectively
Cl O –
A) 0 and –1
B) –1 and 0
C) 1 and –2
D) –2 and 1
E) none of the above
30. In which one of the following structures does the central atom have a formal charge of
+2?
A) SF6
S
F
F
F
FF
F
D) BeCl2
Be
Cl
Cl
B) SO42–
S
O
O
O
O
2-
E) AlCl4–
Al
Cl
ClCl
Cl –
C) O3
O
O
O
31. The formal charge on Cl in the structure shown for the perchlorate ion is
Cl
O
O
O
O–
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
Chapter 10: The Shapes of Molecules
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
38. According to VSEPR theory, a molecule with the general formula AX4 will have a
______ molecular shape.
A) bent D) square planar
B) trigonal planar E) tetrahedral
C) trigonal pyramidal
39. According to VSEPR theory, a molecule with the general formula AX5 will have a
______ molecular shape.
A) tetrahedral D) trigonal bipyramidal
B) trigonal planar E) see–saw
C) trigonal pyramidal
40. Considering all the bonds in a molecule with trigonal bipyramidal geometry, what are
the bond angles present?
A) 120° only D) 60° and 90° only
B) 90° only E) 90°, 120°, and 180°
C) 180° only