Chemistry, 7e (McMurry/Fay)
Chapter 8 Covalent Compounds: Bonding Theories and Molecular Structure
8.1 Multiple-Choice Questions
1) Based on VSEPR theory, which should have the smallest XAX bond angle?
A)
B)
C)
D)
2) Which of the following should be nonplanar?
A) only I
B) only II
C) only III
D) I and III
3) What is the molecular geometry of XeF4?
A) seesaw
B) square planar
C) square pyramidal
D) tetrahedral
4) Which of the following should be nonlinear?
A) only I
B) only II
C) only III
D) II and III
5) What is the molecular geometry of CH3–?
A) T-shaped
B) tetrahedral
C) trigonal planar
D) trigonal pyramidal
6) What is the F—B—F bond angle in BF3?
A) less than 109.5°
B) 109.5°
C) 120°
D) greater than 120°
7) What is the molecular geometry of TeF5–?
A) octahedral
B) seesaw
C) square pyramidal
D) trigonal bipyramidal
8) Which of the following best describes CO2? It has a molecular geometry that is
A) linear molecular shape with no lone pairs on the I atom.
B) linear molecular shape with lone pairs on the I atom.
C) non-linear molecular shape with no lone pairs on the I atom.
D) non-linear molecular shape with lone pairs on the I atom.
9) What is the molecular geometry of SCl4?
A) seesaw
B) square planar
C) square pyramidal
D) tetrahedral
10) What is the smallest bond angle in SF6?
A) 60°
B) 90°
C) 109.5°
D) 120°
11) Which of the following is not a valence bond concept?
A) The greater the overlap between the orbitals on two atoms, the stronger the bond.
B) Lone pair electrons are in atomic orbitals or in hybrid atomic orbitals.
C) Atomic orbitals on two atoms may overlap to form antibonding orbitals.
D) A pair of electrons in a bond is shared by both atoms.
12) Which orbital hybridization is associated with a tetrahedral cloud arrangement?
A) sp
B) sp2
C) sp3
D) sp4
13) What is the angle between adjacent sp3 hybrid orbitals?
A) 90°
B) 109.5°
C) 120°
D) 180°
14) Which of the following is not true?
A) The sp3 hybrid orbitals are degenerate.
B) An sp3 hybrid orbital may hold a lone pair of electrons.
C) An sp3 hybrid orbital may form a sigma bond by overlap with an orbital on another atom.
D) An sp3 hybrid orbital may form a pi bond by overlap with an orbital on another atom.
15) The number of sp2 hybrid orbitals on the carbon atom in CO32- is
A) one.
B) two.
C) three.
D) four.
16) A triple bond is generally composed of
A) three π bonds.
B) two π bonds and one σ bond.
C) one π bond and two σ bonds.
D) three σ bonds.
17) The orbital hybridization on the central carbon atom in CH3CCH is
A) sp.
B) sp2.
C) sp3.
D) sp4.
18) Which of the following would be expected to have sp2 hybridization on atom A?
A) II
B) I and III
C) I, II, and III
D) I and IV
19) The C O bond in COCl2 can be described as
A) a σ bond and a π bond, both involving sp hybrid orbitals on C.
B) a σ bond involving an sp hybrid orbital on C and a π bond involving a p orbital on C.
C) a σ bond and a π bond, both involving sp2 hybrid orbitals on C.
D) a σ bond involving an sp2 hybrid orbital on C and a π bond involving a p orbital on C.
20) Which type of bond produces a charge cloud with a nodal plane containing the bond axis?
A) σ
B) π
C) σ and π
D) neither σ nor π
21) Which atomic orbitals are involved in bonding and which as lone pair orbitals for N2H2?
H — = — H
A) bonding: s on H, sp2 on N lone pair: p on N
B) bonding: sp2 on both H and N lone pair: p on N
C) bonding: s on H, p on N lone pair: sp2 on N
D) bonding: s on H, sp2 and p on N lone pair: sp2 on N
22) What is the hybridization on the N atom in NO2– and in NO3–?
A) sp2 for NO2– and sp3 for NO3–
B) sp3 for NO2– and sp2 for NO3–
C) sp for NO2– and sp2 for NO3–
D) sp2 for both
23) A molecule with the formula XF3 where the element X has the hybridization sp3. Which of the
following elements could be Y?
A) C
B) P
C) B
D) Si
24) The bonds in the polyatomic ion CO32- are classified as
A) ionic.
B) metallic.
C) nonpolar covalent.
D) polar covalent.
25) The dipole moment of ClF is 0.88 D, and its bond length is 163 pm. What is the percent ionic character
of the Cl—F bond?
A) 0.54%
B) 7.8%
C) 11%
D) 25%
26) The dipole moment of BrF is 1.29 D, and its bond length is 178 pm. What is the percent ionic character
of the Br—F bond?
A) 3.9%
B) 8.5%
C) 15%
D) 33%
27) AgCl is found to have 78.1% ionic character, and its gas phase dipole moment is 11.5 D. What is the
distance between the Ag and Cl atoms in gaseous AgCl?
A) 9.19 × 10–10 pm
B) 14.7 pm
C) 307 pm
D) 903 pm
28) The HI bond has a length of 161 pm and 4.92% ionic character. What is the experimental dipole
moment of HI?
A) 0.380 D
B) 0.772 D
C) 3.80 D
D) 7.72 D
29) Which compound below could have a zero dipole moment?
A) CCl2F2 (tetrahedral)
B) CuCl2F2 (tetrahedral)
C) PtCl2F2 (square planar)
D) SCl2F2 (see-saw)
30) Which of the following molecules has polar bonds but has no net dipole?
A) NH3
B) CCl4
C) CHCl3
D) CH4
31) Which of the following compounds exhibits hydrogen bonding?
A) CH3F
B) CH3OCH3
C) (CH3)3N
D) CH3CH2OH
32) Which substance in each of the following pairs is expected to have the larger dispersion forces?
A) Br2 in set I and n-butane in set II
B) Br2 in set I and isobutane in set II
C) I2 in set I and n-butane in set II
D) I2 in set I and isobutane in set II
33) Which of the following molecules will readily form hydrogen bones with H2O?
A) H2
B) C3H8
C) CH4
D) CH3OH
34) Which molecular orbital resembles a p-orbital?
A) σ
B) σ*
C) π
D) π*
35) If an electron is added to H2 it would go into a
A) σ molecular orbital and strengthen the H—H bond.
B) σ molecular orbital and weaken the H—H bond.
C) σ* molecular orbital and strengthen the H—H bond.
D) σ* molecular orbital and weaken the H—H bond.
36) Which molecular orbital resembles a d-orbital?
A) σ
B) σ*
C) π
D) π*
37) Compare the energies of molecular orbitals of homonuclear diatomic molecules with the energies of
the atomic orbitals with which they correlate.
A) Both bonding and antibonding molecular orbitals lie lower in energy than the atomic orbitals.
B) Bonding orbitals are lower and antibonding orbitals are higher in energy than the atomic orbitals.
C) Bonding orbitals are higher and antibonding orbitals are lower in energy than the atomic orbitals.
D) Both bonding and antibonding molecular orbitals are higher in energy than the atomic orbitals.
38) Which molecular orbitals for homonuclear diatomic molecules are degenerate?
A) π molecular orbitals
B) σ molecular orbitals
C) π molecular orbitals and σ molecular orbitals
D) neither π molecular orbitals nor σ molecular orbitals
39) The MO diagram below is appropriate for B2. Based on this diagram, B2
A) has a bond order of one and is diamagnetic.
B) has a bond order of one and is paramagnetic.
C) has a bond order of two and is diamagnetic.
D) has a bond order of two and is paramagnetic.
40) The following MO diagram is appropriate for Li2 and Be2. Based on this diagram,
A) both are stable and diamagnetic.
B) Li2 is stable and diamagnetic, but Be2 is unstable.
C) Be2 is stable and diamagnetic, but Li2 is unstable.
D) Be2 is stable and paramagnetic, but Li2 is unstable.
41) Given that O2 is paramagnetic and has a bond order of 2, and its highest occupied molecular orbital is
antibonding, what would be the expected bond orders for O22- and O22+?
A) 1 for O22– and 3 for O22+
B) 3/2 for O22– and 5/2 for O22+
C) 5/2 for O22– and 3/2 for O22+
D) 3 for O22- and 1 for O22+
42) The paramagnetism of O2 is explained by
A) coordinate covalent bonding.
B) molecular orbital theory.
C) resonance.
D) valence bond theory.
43) Use the following MO diagram for Be2, Be2+, and Be2–. Based on this diagram,
A) Be2+ is more stable than Be2, and Be2 is more stable than Be2–.
B) Be2– is more stable than Be2, and Be2 is more stable than Be2+.
C) Be2+ and Be2– are both more stable than Be2.
D) Be2 is more stable than either Be2+ or Be2–.
44) Which statement concerning any homonuclear diatomic molecule and its 1– ion must be true?
A) X2 must be more stable than X2–.
B) X2 must be less stable than X2–.
C) X2– must be paramagnetic and X2 must be diamagnetic.
D) X2– must be paramagnetic and X2 may be paramagnetic or diamagnetic.
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45) Which is paramagnetic?
A) N22+
B) N22-
C) O22+
D) O22-
46) Based on molecular orbital theory, in order to weaken the N—N bond in N2, electrons should be
A) added.
B) removed.
C) either added or removed.
D) neither added nor removed.
47) In which will the O—O bond be made stronger by removing an electron?
A) only O2
B) only O2–
C) only O22-
D) all of these
48) Molecular orbitals extending over more than two atoms provide an explanation for
A) coordinate covalent bonding.
B) ionic bonding.
C) paramagnetism.
D) resonance.
49) The SO3 molecule can be described as having 3 S—O σ bonds and π molecular orbitals containing
A) 2 electrons.
B) 4 electrons.
C) 6 electrons.
D) 8 electrons.
50) Which is the best description of the bonding in NO3–?
A) 3 N—O σ bonds and no N—O π bonds
B) 3 N—O σ bonds and 3 N—O π bonds
C) no N—O σ bonds and delocalized N—O π molecular orbitals extending over all four atoms
D) 3 N—O σ bonds and delocalized N—O π molecular orbitals extending over all four atoms
51) What is the geometry around the central atom in the following molecular model of NO3–?
A) linear
B) bent
C) trigonal planar
D) trigonal pyramidal
52) What is the geometry around the central atom in the following molecular model of SO2?
A) linear
B) bent
C) trigonal planar
D) trigonal pyramidal
53) What is the geometry around the central atom in the following molecular model of NO2–?
A) linear
B) bent
C) trigonal planar
D) trigonal pyramidal
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54) What is the geometry around the central atom in the following molecular model of NH2–?
A) linear
B) bent
C) trigonal pyramidal
D) tetrahedral
55) What is the geometry around the central atom in the following molecular model of SO32–?
A) linear
B) bent
C) trigonal pyramidal
D) tetrahedral
56) What is the geometry around the central atom in the following molecular model of H3O+?
A) linear
B) bent
C) trigonal pyramidal
D) tetrahedral
57) What is the geometry around the central atom in the following molecular model of NH4+?
A) linear
B) bent
C) trigonal pyramidal
D) tetrahedral
58) What is the geometry around the central atom in the following molecular model of SCl4?
A) trigonal bipyramidal
B) seesaw
C) T-shaped
D) linear
59) What is the geometry around the central atom in the following molecular model of BrF3?
A) trigonal bipyramidal
B) seesaw
C) T-shaped
D) linear
60) What is the geometry around the central atom in the following molecular model of XeF2?
A) trigonal bipyramidal
B) seesaw
C) T-shaped
D) linear