Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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1.
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All
of the following statements concerning valence bond (VB) and molecular orbital (MO) bond theories are
correct EXCEPT a. | MO theory
predicts that electrons are delocalized over the molecule. | b. | in VB theory,
bonding electrons are localized between pairs of atoms. | c. | VB theory
describes a molecular bond as the overlap between two atomic orbitals. | d. | MO theory can
describe molecular bonding in excited states. | e. | VB theory is
used to predict the colors of compounds. | | |
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2.
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How
many sigma (s) bonds and pi
(p) bonds are in
the following molecule?
a. | five
s and two
p | b. | five
s and three
p | c. | five
s and five
p | d. | seven
s and two
p | e. | seven
s and three
p | | |
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3.
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How
many sigma (s) bonds and pi
(p) bonds are in
acetic acid?
a. | six s and one
p | b. | six s and two
p | c. | seven
s and one
p | d. | eight
s and zero
p | e. | eight
s and one
p | | |
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4.
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What
is the maximum number of hybridized orbitals formed by an oxygen atom?
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5.
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What
is the hybridization of the carbon atom in carbon disulfide? a. | sp | b. | sp2 | c. | sp3 | d. | sp3d | e. | sp3d2 | | |
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6.
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What
is the hybridization of the central atom in a molecule with a trigonal-planar
geometry? a. | sp | b. | sp2 | c. | sp3 | d. | sp3d | e. | sp3d2 | | |
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7.
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What
is the molecular geometry around a central atom that is sp3 hybridized and has one
lone electron-pair? a. | bent | b. | linear | c. | trigonal-planar | d. | trigonal-pyramidal | e. | trigonal-bipyramidal | | |
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8.
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What
is the molecular geometry around a central atom that is sp2 hybridized, has three
sigma bonds, and has one pi bond? a. | trigonal-planar | b. | trigonal-pyramidal | c. | trigonal-bipyramidal | d. | linear | e. | tetrahedral | | |
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9.
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What
is the molecular geometry around a central atom that has four sigma bonds and has no lone
electron-pairs? a. | square-pyramidal | b. | tetrahedral | c. | trigonal-planar | d. | square-planar | e. | see-saw | | |
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10.
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Sulfur trioxide is known to be planar with all the oxygen atoms equidistant from the
central sulfur atom. On the basis of these facts, which of the following statements are
CORRECT?
1. | It can be represented by three equivalent resonance
structures. | 2. | The sulfur atom is sp2
hybridized. | 3. | The molecule is nonpolar. | | |
a. | 1 only | b. | 2
only | c. | 3
only | d. | 1 and
2 | e. | 1, 2, and
3 | | |
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11.
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All
of the following statements concerning molecular orbital (MO) theory are correct
EXCEPT a. | the Pauli
exclusion principle is obeyed. | b. | Hund's rule is obeyed. | c. | the combination
of two atomic orbitals creates one molecular orbital. | d. | a bonding
molecular orbital is lower in energy than its parent atomic orbitals. | e. | electrons are
assigned to orbitals of successively higher energy. | | |
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12.
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Atomic orbitals combine most effectively to form molecular orbitals
when a. | electrons in the
orbitals have no spins. | b. | electrons in the orbitals have the same
spin. | c. | the atomic orbitals are hybridized. | d. | the atomic
orbitals have similar energies. | e. | metals combine with nonmetals. | | |
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13.
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A
molecular orbital that decreases the electron density between two nuclei is said to be
____. a. | antibonding | b. | bonding | c. | hybridized | d. | dipolar | e. | nonpolar | | |
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Molecular Orbital Theory
The following molecular orbital diagram may be used for the following
problems. For oxygen and fluorine, the s2p orbital should be lower in energy than the p2p.
However, the diagram will still yield correct bond order and magnetic behavior for these
molecules.
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14.
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According to molecular orbital theory, which of the following species is least likely
to exist? a. | H2- | b. | F22+ | c. | C22- | d. | Li2 | e. | B22+ | | |
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15.
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According to molecular orbital theory, what is the bond order of nitrogen,
N2?
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16.
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Refer
to Molecular Orbital Theory. Consider the molecules Be2, B2, C2, and
F2. Which two molecules have the same bond order? a. | Be2
and B2 | b. | B2 and C2 | c. | C2
and F2 | d. | Be2 and C2 | e. | B2
and F2 | | |
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17.
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Use
molecular orbital theory to predict which species is paramagnetic.
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18.
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Refer
to Molecular Orbital Theory. What is the molecular orbital configuration of
N2? a. | [core electrons]
(s2s)2 (s*2s)2 (p2p)2 (s2p)2 (s*2p)2 | b. | [core electrons] (s2s)2 (s*2s)2 (p2p)2 (s2p)2 (p*2p)2 | c. | [core electrons]
(s2s)2 (s*2s)2 (p2p)4 (s2p)2 | d. | [core electrons] (s2s)2 (s*2s)2 (p2p)4 (s2p)2 (p*2p)4 | e. | [core electrons]
(s2s)2 (s*2s)2 (p2p)4 (p*2p)2 | | |
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19.
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Which
molecule will have the following valence molecular orbital level energy
diagram?
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20.
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The
following valence molecular orbital energy level diagram is appropriate for which one of the listed
species?
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