Chapter 8: Bonding: General Concepts
1. The force between two bodies having identical electric charges
A)
is a force of repulsion
B)
is a force of repulsion if the charges are negative, and one of attraction if they are
positive
C)
increases as the bodies are moved further apart
D)
is independent of the distance between them
E)
is directly proportional to the distance between them
2. Which of the following groups contains no ionic compounds?
A)
HCN, NO2, Ca(NO3)2
B)
PCl5, LiBr, Zn(OH)2
C)
KOH, CCl4, SF4
D)
NaH, CaF2, NaNH2
E)
CH2O, H2S, NH3
3. In which pair do both compounds exhibit predominantly ionic bonding?
A)
SCl6 and HF
B)
Na2SO3 and NH3
C)
KI and O3
D)
LiF and H2O
E)
LiBr and MgO
4. When a metal reacts with a nonmetal a covalent bond is formed.
5. A nonpolar covalent bond results from the unequal sharing of a pair of electrons between
atoms in a molecule.
6. Atoms having equal or nearly equal electronegativities are expected to form
A)
no bonds
B)
polar covalent bonds
C)
nonpolar covalent bonds
D)
ionic bonds
E)
covalent bonds
7. Choose the compound with the most ionic bond.
A)
LiCl
B)
KF
C)
NaCl
D)
LiF
E)
KCl
8. Atoms with greatly different electronegativity values are expected to form
A)
no bonds
B)
covalent bonds
C)
triple bonds
D)
ionic bonds
E)
none of these
9. Which of the following bonds is least polar?
A)
C—O
B)
H—C
C)
S—Cl
D)
Br—Br
E)
They are all nonpolar.
10. For the elements Cs, F, and P, the order of increasing electronegativity is:
A)
Cs < F < P
B)
Cs < P < F
C)
P < F < Cs
D)
F < Cs < P
E)
none of these
11. For the elements Cs, F, and Cl, the order of increasing electronegativity is:
A)
F < Cl < Cs
B)
Cs < Cl < F
C)
Cl < Cs < F
D)
F < Cs < Cl
E)
none of these
12. In the gaseous phase, which of the following diatomic molecules would be the most polar?
A)
CsF
B)
CsCl
C)
NaCl
D)
NaF
E)
LiF
13. Based on electronegativities, which of the following would you expect to be most ionic?
A)
N2
B)
CaF2
C)
CO2
D)
CH4
E)
CF4
14. In which case is the bond polarity incorrect?
A)
+H–F–
B)
+K–O–
C)
+Mg–H–
D)
+Cl–I–
E)
+Si–S–
15. Metals typically have _______ electronegativity values.
A)
high
B)
low
C)
negative
D)
no
E)
two of these
16. The electron pair in a C-F bond could be considered
A)
closer to C because carbon has a larger radius and thus exerts greater control over
the shared electron pair
B)
closer to F because fluorine has a higher electronegativity than carbon
C)
closer to C because carbon has a lower electronegativity than fluorine
D)
an inadequate model since the bond is ionic
E)
centrally located directly between the C and F
17. Based on electronegativity differences, which of the following is most likely to be ionic?
A)
CaF2
B)
Br2
C)
BH3
D)
NO
E)
CF4
18. What is the correct order of the following bonds in terms of decreasing polarity?
A)
N-Cl, P-Cl, As-Cl
B)
P-Cl, N-Cl, As-Cl
C)
As-Cl, N-Cl, P-Cl
D)
P-Cl, As-Cl, N-Cl
E)
As-Cl, P-Cl, N-Cl
19. Which of the following bonds would be the most polar without being considered ionic?
A)
Mg-O
B)
C-O
C)
O-O
D)
Si-O
E)
N-O
20. Which of the following bonds would be the least polar, yet still be considered polar
covalent?
A)
Mg-O
B)
C-O
C)
O-O
D)
Si-O
E)
N-O
21. In which of the following compounds does the bond between the central atom and bromine
have the greatest ionic character?
A)
LiBr
B)
KBr
C)
SeBr2
D)
AsBr3
E)
CaBr2
22. Which of the following statements is incorrect?
A)
Ionic bonding results from the transfer of electrons from one atom to another.
B)
Dipole moments result from the unequal distribution of electrons in a molecule.
C)
The electrons in a polar bond are found nearer to the more electronegative element.
D)
A molecule with very polar bonds can be nonpolar.
E)
Linear molecules cannot have a net dipole moment.
23. Which of the following molecules has no dipole moment?
A)
CO2
B)
NH3
C)
H2O
D)
all
E)
none
24. Which of the following has the smallest radius?
A)
Br–
B)
S2–
C)
Xe
D)
Ca2+
E)
Kr
25. Which of these is an isoelectronic series?
A)
Na+, K+, Rb+, Cs+
B)
K+, Ca2+, Ar, S2–
C)
Na+, Mg2+, S2–, Cl–
D)
Li, Be, B, C
E)
none of these (A-D)
26. Which of the following has the smallest radius?
A)
K+
B)
Cl–
C)
Rb+
D)
S2–
E)
Ar
27. Which of the following has the smallest radius?
A)
F–
B)
Ne
C)
O2–
D)
Mg2+
E)
Na+
28. Which of the following pairs is isoelectronic?
A)
Li+ and K+
B)
Na+ and Ne
C)
I– and Cl–
D)
S2– and Ne
E)
Al3+ and B3+
29. Which of the following arrangements is in order of increasing size?
A)
Ga3+ > Ca2+ > K+ > Cl– > S2–
B)
S2– > Cl– > K+ > Ca2+ > Ga3+
C)
Ga3+ > S2– > Ca2+ > Cl– > K+
D)
Ga3+ > Ca2+ > S2– > Cl– > K+
E)
Ga3+ > Ca2+ > S2– > K+ > Cl–
30. The size in a series of isoelectronic ions increases as the nuclear charge increases.
31. Which of the following species would be expected to have the lowest ionization energy?
A)
F–
B)
Ne
C)
O2–
D)
Mg2+
E)
Na+
32. Which of the following ionic compounds has the largest lattice energy (i.e., the lattice
energy most favorable to a stable lattice)?
A)
BaO
B)
BeO
C)
CsI
D)
NaBr
E)
BaS
33. Which of the following ionic compounds has the smallest lattice energy (i.e., the lattice
energy least favorable to a stable lattice)?
A)
LiF
B)
CsI
C)
NaCl
D)
BaO
E)
MgO
34. Calculate the lattice energy for LiCl(s) given the following:
sublimation energy for Li(s)
+166 kJ/mol
Hf for Cl(g)
+119 kJ/mol
first ionization energy of Li(g)
+520. kJ/mol
electron affinity of Cl(g)
–349 kJ/mol
enthalpy of formation of LiCl(s)
–409 kJ/mol
A)
47 kJ/mol
B)
171 kJ/mol
C)
–580 kJ/mol
D)
–865 kJ/mol
E)
none of these
35. Which of the following statements are true concerning ionic bonding?
A)
Ionic bonding occurs between a metal, which has a high affinity for electrons, and
a nonmetal, which loses electrons relatively easy.
B)
CaCl2 forms because Ca2+ is always a more stable species than the calcium atom
alone.
C)
Compounds with ionic bonds tend to have low melting points.
D)
The electronegativity difference between the bonding atoms of ionic compounds is
small since the electrons are not shared but rather held together by electrostatic
forces.
E)
All of the above statements are false.
36. Which of the following statements concerning lattice energy is false?
A)
It is often defined as the energy released when an ionic solid forms from its ions.
B)
MgO has a larger lattice energy than NaF.
C)
The lattice energy for a solid with 2+ and 2– ions should be two times that for a
solid with 1+ and 1– ions.
D)
MgO has a larger lattice energy than LiF.
E)
All of these are true.
37. Given the following information:
Li(s) → Li(g)
enthalpy of sublimation of Li(s) = 166 kJ/mol
HBr(g) → H(g) + Br(g)
bond energy of HBr = 363 kJ/mol
Li(g) → Li+(g) + e–
ionization energy of Li(g) = 520. kJ/mol
Br(g) + e– → Br–(g)
electron affinity of Br(g) = –325 kJ/mol
Li+(g) + Br–(g) → LiBr(s)
lattice energy of LiBr(s) = –809 kJ/mol
H2(g) → 2H(g)
bond energy of H2 = 432 kJ/mol
Calculate the change in enthalpy for:
2Li(s) + 2HBr(g) → H2(g) + 2LiBr(s)
A)
262 kJ
B)
–602 kJ
C)
–517 kJ
D)
–992 kJ
E)
none of these
38. The first electron affinity value for oxygen is _______ and the second electron affinity value
is ________.
A)
unfavorable (endothermic), favorable (exothermic)
B)
unfavorable (endothermic), unfavorable (endothermic)
C)
favorable (exothermic), favorable (exothermic)
D)
favorable (exothermic), unfavorable (endothermic)
E)
More information is needed.
39. In the reaction between magnesium and sulfur, the magnesium atoms
A)
become anions
B)
become cations
C)
become part of polyatomic ions
D)
share electrons with sulfur
E)
crystallize
40. When electrons in a molecule are not found between a pair of atoms but move throughout
the molecule, this is called
A)
ionic bonding
B)
covalent bonding
C)
polar covalent bonding
D)
delocalization of the electrons
E)
a dipole moment
41. Which of the following statements is false?
A)
Models are human interpretations, not the same as reality.
B)
Models are often wrong.
C)
Models usually start out simple and become more complex over time.
D)
We often learn more when a model is wrong than when it is right.
E)
A model should be discarded when any exception to it is found.
42. Choose the molecule with the strongest bond.
A)
F2
B)
Cl2
C)
Br2
D)
I2
E)
All are equal.
43. Choose the molecule with the strongest bond.
A)
HF
B)
HCl
C)
HBr
D)
HI
E)
All are equal.
44. Choose the molecule with the strongest bond.
A)
CH4
B)
H2O
C)
NH3
D)
HF
E)
All are equal
45. Which of the following molecules exhibits the greatest bond energy?
A)
F2
B)
Cl2
C)
Br2
D)
I2
E)
all the same
46. As the number of bonds between two carbon atoms increases, which one of the following
decreases?
A)
number of electrons between the carbon atoms
B)
bond energy
C)
bond length
D)
all of these
E)
none of these
47. Using the following bond energies:
Bond Energy (kJ/mol)
839
413
495
799
467
estimate the heat of combustion for one mole of
acetylene:
C2H2(g) + O2(g) → 2CO2(g) + H2O(g)
A)
1228 kJ
B)
–1228 kJ
C)
–447 kJ
D)
+447 kJ
E)
+365 kJ
48. Using the following data reactions:
H° (kJ)
H2(g) + F2(g) → 2HF(g)
–542
H2(g) → 2H(g)
432
F2(g) → 2F(g)
154
calculate the energy of an H-F bond.
A)
1128 kJ
B)
22 kJ
C)
44 kJ
D)
271 kJ
E)
564 kJ
49. Given the following bond energies:
C–C
347 kJ/mol
C=C
614 kJ/mol
C–O
358 kJ/mol
C=O
799 kJ/mol
C–H
413 kJ/mol
O–H
463 kJ/mol
O–O
146 kJ/mol
estimate H for the reaction H2O2 + CH3OH → H2CO + 2H2O.
A)
–345 kJ
B)
–199 kJ
C)
–105 kJ
D)
+199 kJ
E)
+345 kJ
50. Given the following information:
Br2 bond energy = 193 kJ/mol
F2 bond energy = 154 kJ/mol
Br2(g) + F2(g) → BrF3(g)
H° = –384 kJ/mol
calculate the Br-F bond energy.
A)
244 kJ/mol
B)
237 kJ/mol
C)
712 kJ/mol
D)
128 kJ/mol
E)
none of these
51. Consider the following reaction:
A2 + B2 → 2AB H = –365 kJ
The bond energy for A2 is half the amount of AB. The bond energy of B2 = 447 kJ/mol.
What is the bond energy of A2?
A)
812 kJ/mol
B)
630 kJ/mol
C)
271 kJ/mol
D)
–183 kJ/mol
E)
none of these
52. A double bond occurs when two atoms share two pairs of electrons.
53. As indicated by Lewis structures, which of the following would probably not exist as a
stable molecule?
A)
CH3OH
B)
CH2O
C)
CH3O
D)
C2H2
E)
C3H4
54. In the Lewis structure for elemental nitrogen there is (are)
A)
a single bond between the nitrogens
B)
a double bond between the nitrogens
C)
a triple bond between the nitrogens
D)
three unpaired electrons
E)
none of the above
55. Complete the Lewis structure for the molecule:
This molecule has __________ single bonds and __________ multiple bonds.
A)
4, 2
B)
6, 3
C)
11, 5
D)
11, 2
E)
13, 0
Draw the Lewis structures of the molecules below and use them to answer the following
questions:
I.
BH3
II.
NO2
III.
SF6
IV.
O3
V.
PCl5
56. Which of the molecules obeys the octet rule?
A)
I
B)
II
C)
III
D)
IV
E)
V
57. How many of the molecules have no dipole moment?
A)
1
B)
2
C)
3
D)
4
E)
They are all polar.
58. Which of these molecules show resonance?
A)
I, II
B)
II, IV
C)
II, V
D)
III, IV
E)
III, V
Using the following electronegativity values:
C
2.5
Cl
3.0
H
2.1
O
3.5
select from the following group the molecule that fits the given statement:
a)
CH3CHO
b)
CO2
c)
CH3Cl
d)
C2H6
e)
none
59. This molecule contains a carbon atom with trigonal planar geometry.
A)
CH3CHO
B)
CO2
C)
CH3Cl
D)
C2H6
E)
none of these
60. This molecule is the most polar.
A)
CH3CHO
B)
CO2
C)
CH3Cl
D)
C2H6
E)
All are nonpolar.
61. This molecule shows the smallest number of lone pairs in its Lewis structure.
A)
CH3CHO
B)
CO2
C)
CH3Cl
D)
C2H6
E)
All have zero lone pairs.
Consider the compound crotonaldehyde, whose skeleton is:
62. How many electrons must be shown (as bonding or nonbonding electrons) in the Lewis
structure of this molecule?
A)
12
B)
18
C)
24
D)
28
E)
32
63. How many nonbonding electrons appear in the Lewis structure of this molecule?
A)
2
B)
4
C)
6
D)
8
E)
10
64. Which carbon in this molecule has tetrahedral bonding?
A)
1
B)
2
C)
3
D)
4
E)
all
65. Which of the following molecules contains a double bond?
A)
CO2
B)
NH3
C)
H2O
D)
all
E)
none
66. When molten sulfur reacts with chlorine gas, a vile-smelling orange liquid forms that is
found to have the empirical formula SCl. Which of the following could be the correct Lewis
structure for this compound?
A)
B)
C)
D)
E)
:
Given the following Lewis structure:
67. How many unshared pairs of electrons are present in this molecule?
A)
0
B)
1
C)
2
D)
3
E)
4
68. How many electrons are shared between carbons 1 and 2?
A)
0
B)
2
C)
4
D)
6
E)
8
69. Which of the following compounds contains only one unshared pair of valence electrons?
A)
NH3
B)
H2O
C)
CH4
D)
NaCl
E)
BF3
70. The Lewis structure for CHCl3 has nine lone electron pairs.
71. Which of the following atoms cannot exceed the octet rule in a molecule?
A)
N
B)
S
C)
P
D)
I
E)
All of the atoms (A-D) can exceed the octet rule.
72. As indicated by Lewis structures, which of the following species could probably not exist as
a stable molecule?
A)
NH3
B)
N2H2
C)
N2H4
D)
N2H6
E)
N2O4
73. The Lewis structure for H3BO3 is
A)
B)
C)
D)
E)
74. In the Lewis structure for ICl2–, how many lone pairs of electrons are around the central
iodine atom?
A)
0
B)
1
C)
2
D)
3
E)
4
75. In the Lewis structure for SF6, the central sulfur atom shares __________ electrons.
A)
4
B)
8
C)
10
D)
12
E)
None of the above, because SF6 is an ionic compound.
76. Which of the following Lewis structures best describes BF3?
A)
B)
C)
D)
E)
77. Which of the following has an incomplete octet in its Lewis structure?
A)
SO2
B)
ICl
C)
CO2
D)
F2
E)
NO
Consider the following molecules.
I.
BF3
II.
CHBr3 (C is the central atom)
III.
Br2
IV.
XeCl2
V.
CO
VI.
SF4
Select the molecule(s) that fit the given statement.
78. These molecules violate the octet rule.
A)
I, II, IV