84) Structural changes around a double bond in the __________ portion of the rhodopsin molecule
trigger the chemical reactions that result in vision.
A) protein
B) opsin
C) retinal
D) cones
E) rods
85) 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
86) 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
87) 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
88) In molecular orbital theory, the σ1s orbital is __________ and the σ1s* orbital is __________ in the
H2 molecule.
A) filled, filled
B) filled, empty
C) filled, half-filled
D) half-filled, filled
E) empty, filled
89) 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
90) 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
91) An antibonding π orbital contains a maximum of __________ electrons.
A) 1
B) 2
C) 4
D) 6
E) 8
92) 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
93) A molecular orbital can accommodate a maximum of __________ electron(s).
A) one
B) two
C) four
D) six
E) twelve
94) 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
95) 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 π2p MOs is higher than that of the σ2p MO
E) the F F bond enthalpy is very low
96) 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
97) Based on molecular orbital theory, there are __________ unpaired electrons in the OF+ ion.
A) 0
B) 3
C) 1
D) 2
E) 1/2
98) Based on molecular orbital theory, the bond order of the N N bond in the N2 molecule is
__________.
A) 0
B) 1
C) 2
D) 3
E) 5
99) 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
100) 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
101) Based on molecular orbital theory, the bond order of the C C bond in the C2 molecule is
__________.
A) 0
B) 1
C) 2
D) 3
E) 4
102) Of the following, only __________ appears to gain mass in a magnetic field.
A) C2
B) N2
C) F2
D) O2
E) Li2
103) 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
104) 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
105) 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
106) 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
107) 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
108) 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.
109) 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°
29
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°
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 __________.
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 bonds 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 H2CC 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) According to VSEPR theory, if there are six electron domains in the valence shell of an atom, they
will be arranged in a(n) __________ geometry.
A) linear
B) tetrahedral
C) trigonal planar
D) trigonal bipyramidal
E) octahedral
2) The electron-domain geometry and molecular geometry of ammonia are __________ and
__________, respectively.
A) octahedral, T-shaped
B) trigonal bipyramidal, T-shaped
C) tetrahedral, trigonal pyramidal
D) octahedral, trigonal planar
E) T-shaped, trigonal planar
3) The electron-domain geometry and molecular geometry of boron trifluoride are __________ and
__________, respectively.
A) octahedral, T-shaped
B) trigonal bipyramidal, T-shaped
C) tetrahedral, trigonal pyramidal
D) trigonal planar, trigonal planar
E) T-shaped, trigonal planar
4) Using the VSEPR model, the electron-domain geometry of the central atom in BF3 is __________.
A) linear
B) trigonal planar
C) tetrahedral
D) trigonal bipyramidal
E) octahedral
5) Using the VSEPR model, the electron-domain geometry of the central atom in SF2 is __________.
A) linear
B) trigonal planar
C) tetrahedral
D) trigonal bipyramidal
E) octahedral
6) Using the VSEPR model, the electron-domain geometry of the central atom in SF4 is __________.
A) linear
B) trigonal planar
C) tetrahedral
D) trigonal bipyramidal
E) octahedral
7) Using the VSEPR model, the electron-domain geometry of the central atom in BrF4– is __________.
A) linear
B) trigonal planar
C) tetrahedral
D) trigonal bipyramidal
E) octahedral
8) Using the VSEPR model, the molecular geometry of the central atom in XeF2 is __________.
A) linear
B) trigonal planar
C) tetrahedral
D) bent
E) trigonal pyramidal
9) Using the VSEPR model, the molecular geometry of the central atom in BF3 is __________.
A) linear
B) trigonal planar
C) tetrahedral
D) bent
E) trigonal pyramidal
10) Using the VSEPR model, the molecular geometry of the central atom in CF4 is __________.
A) linear
B) trigonal planar
C) tetrahedral
D) bent
E) trigonal pyramidal
11) Using the VSEPR model, the molecular geometry of the central atom in SO2 is __________.
A) linear
B) trigonal planar
C) tetrahedral
D) bent
E) trigonal pyramidal
12) Using the VSEPR model, the molecular geometry of the central atom in NCl3 is __________.
A) linear
B) trigonal planar
C) tetrahedral
D) bent
E) trigonal pyramidal
13) Using the VSEPR model, the molecular geometry of the central atom in XeF4 is __________.
A) tetrahedral
B) seesaw
C) square planar
D) trigonal bipyramidal
E) square pyramidal
14) The bond angles in a trigonal bipyramidal molecule are __________ degrees.
A) 120
B) 109.5
C) 180
D) 45
E) <45
15) According to valence bond theory, which orbitals overlap in the formation of the bond in N2?
A) 1s
B) 1p
C) 2s
D) 2p
E) 3s
16) The hybrid orbital set used by the central atom in NO3– is __________.
A) sp
B) sp2
C) sp3
D) sp3d
E) sp3d2
17) The hybrid orbital set used by the central atom in NCl3 is __________.
A) sp
B) sp2
C) sp3
D) sp3d
E) sp3d2
18) The hybrid orbital set used by the central atom in KrF2 is __________.
A) sp
B) sp2
C) sp3
D) sp3d
E) sp3d2
9.4 Short Answer Questions
1) What is the molecular geometry of a molecule that has three bonding and two non-bonding domains?
2) In the valence shell of an atom there are six electron domains. They will be arranged in a (an)
__________ geometry.
3) What are the three bond angles in the trigonal bipyramidal structure?
4) Three molecules have similar electron domains, but different molecular shapes. Why?
5) The 1s hydrogen orbital overlaps with the __________ iodine orbital in HI.
6) A covalent bond in which overlap regions lie above and below an internuclear axis is called a(n)
__________.
7) The sensation of vision results from a nerve impulse that is triggered by the separation of retinal from
__________.
8) In molecular orbital theory the stability of a covalent body is related to its __________.
9) Each molecular orbital can accommodate, at most, two electrons with their spins paired. This is
called the __________.
10) The more unpaired electrons in a species, the stronger is the force of magnetic attraction. This is
called __________.
1) Possible shapes of AB3 molecules are linear, trigonal planar, and T-shaped.
2) Boron trifluoride has three bonding domains and its electron domain geometry is trigonal planar.
3) Electron domains for single bonds exert greater force on adjacent domains than the electron domains
for multiple bonds.
4) The quantitative amount of charge separation in a diatomic molecule contributes to the dipole
moment of that molecule.
5) XeF4 is a polar molecule.
6) Hybridization is the process of mixing atomic orbitals as atoms approach each other to form a bond.
7) Electrons in core orbitals contribute to atom bonding.
8) Nitrogen is colorless because the minimum energy to excite an electron is in the ultraviolet section of
the spectrum.