21
67) The bond order of any molecule containing equal numbers of bonding and antibonding electrons is
________.
A) 0
B) 1
C) 2
D) 3
E) 1/2
68) In comparing the same two atoms bonded together, the ________ the bond order, the ________ the
bond length, and the ________ the bond energy.
A) greater, shorter, greater
B) greater, greater, greater
C) greater, longer, greater
D) smaller, longer, smaller
E) smaller, greater, greater
69) In comparing the same two atoms bonded together, the ________ the bond order, the ________ the
bond length, and the ________ the bond energy.
A) greater, shorter, greater
B) greater, greater, greater
C) greater, longer, greater
D) greater, greater, smaller
E) smaller, greater, greater
70) Based on molecular orbital theory, the bond orders of the H—H bonds in H2, H2+, and H2– are
________, respectively
A) 1, 0, and 0
B) 1, 1/2, and 0
C) 1, 0, and 1/2
D) 1, 1/2, and 1/2
E) 1, 2, and 0
71) Based on molecular orbital theory, the bond order of the H—H bond in the H2+ ion is ________.
A) 0
B) 1/2
C) 1
D) 3/2
E) 2
72) An antibonding π orbital contains a maximum of ________ electrons.
A) 1
B) 2
C) 4
D) 6
E) 8
73) According to MO theory, overlap of two s atomic orbitals produces ________.
A) one bonding molecular orbital and one hybrid orbital
B) two bonding molecular orbitals
C) two bonding molecular orbitals and two antibonding molecular orbitals
D) two bonding molecular orbitals and one antibonding molecular orbital
E) one bonding molecular orbital and one antibonding molecular orbital
74) A molecular orbital can accommodate a maximum of ________ electron(s).
A) 1
B) 2
C) 4
D) 6
E) 12
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75) Molecular Orbital theory correctly predicts paramagnetism of oxygen gas, O2. This is because
________.
A) the bond order in O2 can be shown to be equal to 2.
B) there are more electrons in the bonding orbitals than in the antibonding orbitals.
C) the energy of the π2p MOs is higher than that of the σ2p MO
D) there are two unpaired electrons in the MO electron configuration of O2
E) the O—O bond distance is relatively short
76) Molecular Orbital theory correctly predicts diamagnetism of fluorine gas, F2. This is because
________.
A) the bond order in F2 can be shown to be equal to 1.
B) there are more electrons in the bonding orbitals than in the antibonding orbitals.
C) all electrons in the MO electron configuration of F2 are paired.
D) the energy of the π2pMOs is higher than that of the σ2p MO
E) the F—F bond enthalpy is very low
77) Based on molecular orbital theory, the only molecule in the list below that has unpaired electrons is
________.
A) C2
B) N2
C) F2
D) O2
E) Li2
78) Based on molecular orbital theory, there is/are ________ unpaired electron(s) in the OF+ ion.
A) 0
B) 3
C) 1
D) 2
E) 1/2
79) Based on molecular orbital theory, the bond order of the N—N bond in the N22+ ion is ________.
A) 0
B) 3
C) 1
D) 2
E) 1/2
80) Based on molecular orbital theory, the bond order of the Be—Be bond in the Be2 molecule is ________.
A) 0
B) 1
C) 2
D) 3
E) 4
81) Of the following, only ________ appears to gain mass in a magnetic field.
A) C2
B) N2
C) F2
D) O2
E) Li2
82) Of the following, ________ appear(s) to gain mass in a magnetic field.
B2 N2 O2
A) O2 only
B) N2 only
C) B2 and N2
D) N2 and O2
E) B2 and O2
83) According to MO theory, overlap of two p atomic orbitals produces ________.
A) two bonding molecular orbitals
B) one bonding molecular orbital and one antibonding molecular orbital
C) two bonding molecular orbitals and two antibonding molecular orbitals
D) two bonding molecular orbitals and one antibonding molecular orbital
E) three bonding molecular orbitals and three antibonding molecular orbitals
84) According to MO theory, overlap of two p atomic orbitals produces ________.
A) one π MO and one σ* MO
B) one π MO and one σ MO
C) one π MO and one π* MO or one σ MO and one σ* MO
D) one π+ MO and one σ* MO
E) two π MOs, two π+ MOs, one σ MO, and one σ* MO
85) An antibonding MO ________ the corresponding bonding MO.
A) is always lower in energy than
B) can accommodate more electrons than
C) can accommodate fewer electrons than
D) is always higher in energy than
E) is always degenerate with
86) The more effectively two atomic orbitals overlap, ________.
A) the more bonding MOs will be produced by the combination
B) the higher will be the energy of the resulting bonding MO and the lower will be the energy of the
resulting antibonding MO
C) the higher will be the energies of both bonding and antibonding MOs that result
D) the fewer antibonding MOs will be produced by the combination
E) the lower will be the energy of the resulting bonding MO and the higher will be the energy of the
resulting antibonding MO
26
87) The bond order of a homonuclear diatomic molecule can be decreased by ________.
A) removing electrons from a bonding MO or adding electrons to an antibonding MO
B) adding electrons to a bonding MO or removing electrons from an antibonding MO
C) adding electrons to any MO
D) removing electrons from any MO
E) The bond order of a homonuclear diatomic molecule cannot be decreased by any means.
88) The order of MO energies in B2, C2, and N2 (σ2p > π2p), is different from the order in O2, F2, and
Ne2 (σ2p > π2p). This is due to ________.
A) less effective overlap of p orbitals in O2, F2, and Ne2
B) the more metallic character of boron, carbon and nitrogen as compared to oxygen, fluorine, and neon
C) greater 2s-2p interaction in O2, F2, and Ne2
D) greater 2s-2p interaction in B2, C2, and N2
E) less effective overlap of p orbitals in B2, C2, and N2
9.2 Bimodal Questions
1) For a molecule with the formula AB2, the molecular shape is ________.
A) linear or bent
B) linear or trigonal planar
C) linear or T-shaped
D) T-shaped
E) trigonal planar
2) For a molecule with the formula AB3, the molecular shape is ________.
A) linear, octahedral, or bent
B) linear, bent, or trigonal planar
C) linear, bent, or T-shaped
D) tetrahedral
E) trigonal planar, trigonal pyramidal, or T-shaped
3) The molecular geometry of ________ is square planar.
A) CCl4
B) XeF4
C) PH3
D) XeF2
E) ICl3
4) The molecular geometry of the CS2 molecule is ________.
A) linear
B) bent
C) tetrahedral
D) trigonal planar
E) T-shaped
5) The molecular geometry of the SiH2Cl2 molecule is ________.
A) trigonal planar
B) tetrahedral
C) trigonal pyramidal
D) octahedral
E) T-shaped
6) The molecular geometry of the PHCl2 molecule is ________.
A) bent
B) trigonal planar
C) trigonal pyramidal
D) tetrahedral
E) T-shaped
7) The molecular geometry of the CHCl3 molecule is ________.
A) bent
B) trigonal planar
C) trigonal pyramidal
D) tetrahedral
E) T-shaped
8) The molecular geometry of the SF2 molecule is ________.
A) linear
B) bent
C) trigonal planar
D) tetrahedral
E) octahedral
9) The molecular geometry of the PF4+ ion is ________.
A) octahedral
B) tetrahedral
C) trigonal pyramidal
D) trigonal planar
E) trigonal bipyramidal
10) The F-B-F bond angle in the BF2– ion is approximately ________.
A) 90°
B) 109.5°
C) 120°
D) 180°
E) 60°
11) The Cl-Si-Cl bond angle in the SiCl2F2 molecule is approximately ________.
A) 90°
B) 109.5°
C) 120°
D) 180°
E) 60°
12) The F-B-F bond angle in the BF3 molecule is ________.
A) 90°
B) 109.5°
C) 120°
D) 180°
E) 60°
13) The O-S-O bond angle in SO2 is slightly less than ________.
A) 90°
B) 109.5°
C) 120°
D) 180°
E) 60°
14) The F-N-F bond angle in the NF3 molecule is slightly less than ________.
A) 90°
B) 109.5°
C) 120°
D) 180°
E) 60°
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15) The molecular geometry of the H3O+ ion is ________.
A) linear
B) tetrahedral
C) bent
D) trigonal pyramidal
E) octahedral
16) The electron-domain geometry of a sulfur-centered compound is trigonal bipyramidal. The
hybridization of the central sulfur atom is ________.
A) sp
B) sp2
C) sp3
D) sp3d
E) sp3d2
17) The hybridization of orbitals on the central atom in a molecule is sp. The electron–domain geometry
around this central atom is ________.
A) octahedral
B) linear
C) trigonal planar
D) trigonal bipyramidal
E) tetrahedral
18) The hybridization of orbitals on the central atom in a molecule is sp2. The electron-domain geometry
about this central atom is ________.
A) octahedral
B) linear
C) trigonal planar
D) trigonal bipyramidal
E) tetrahedral
19) The hybridization of the carbon atom in carbon dioxide is ________.
31
A) sp
B) sp2
C) sp3
D) sp3d
E) sp3d2
20) The hybridization of the central atom in the XeF4 molecule is ________.
A) sp
B) sp2
C) sp3
D) sp3d
E) sp3d2
21) The electron-domain geometry of the AsF6– ion is octahedral. The hybrid orbitals used by the As atom
for bonding are ________ orbitals.
A) sp2d2
B) sp3
C) sp3d
D) sp3d2
E) sp2
22) In order to produce sp3 hybrid orbitals, ________ s atomic orbital(s) and ________ p atomic orbital(s)
must be mixed.
A) one, two
B) one, three
C) one, one
D) two, two
E) two, three
23) In order to produce sp2 hybrid orbitals, ________ s atomic orbital(s) and ________ p atomic orbital(s)
must be mixed.
A) one, two
B) one, three
C) one, one
D) two, two
E) two, three
24) The angles between sp2 orbitals are ________.
A) 45°
B) 180°
C) 90°
D) 109.5°
E) 120°
25) There are ________ σ and ________ π bonds in the H—C≡C—H molecule.
A) 3 and 2
B) 3 and 4
C) 4 and 3
D) 2 and 3
E) 5 and 0
26) There are ________ σ and ________ π bond(s) in the H2C=CH2 molecule.
A) 3 and 2
B) 3 and 4
C) 4 and 3
D) 2 and 3
E) 5 and 1
27) There are ________ σ and ________ π bonds in the H2C=C=CH2 molecule.
A) 4, 2
B) 6, 4
C) 2, 2
D) 2, 6
E) 6, 2
28) The total number of π bonds in the H—C≡C—C≡C—C≡N molecule is ________.
A) 3
B) 4
C) 6
D) 9
E) 12
29) There is/are ________ σ bond(s) in the molecule below.
A) 1
B) 2
C) 12
D) 13
E) 18
30) There is/are ________ π bond(s) in the molecule below.
A) 0
B) 1
C) 2
D) 4
E) 16
31) There is/are ________ π bond(s) in the molecule below.
A) 7
B) 6
C) 2
D) 1
E) 0
32) The Lewis structure of carbon monoxide is given below. The hybridizations of the carbon and oxygen
atoms in carbon monoxide are ________ and ________, respectively.
: C ≡ O :
A) sp, sp3
B) sp2, sp3
C) sp3, sp2
D) sp, sp
E) sp2, sp2
9.3 Algorithmic Questions
1) ClF3 has “T-shaped” geometry. There is/are ________ non-bonding domain(s) in this molecule.
A) 4
B) 2
C) 3
D) 1
E) 0
2) The electron domain and molecular geometry of SO3 are ________.
A) trigonal bipyramidal, trigonal planar
B) trigonal planar, bent
C) trigonal bipyramidal, T-shaped
D) trigonal planar, trigonal planar
E) octahedral, seesaw