Chapter 3:
Molecular Shape and Structure
1. What does the VSEPR model dictate about areas in a molecule with high electron
density?
a. That they will repel each other.
b. That they will attract each other.
c. That they will repel each other if they are electrons in a bond.
d. That they will attract each other only if they are electrons in a lone pair.
Answer:
A
2. How do lone pairs of electron density influence the shape of a molecule?
a. They occupy minimal space and repel other electrons, thus influencing only slightly
the overall molecular shape.
b. They occupy space and repel other electrons, thus influencing overall molecular
shape.
c. They occupy space and attract other electrons, thus influencing overall molecular
shape
d. They do not actually influence the shape.
Answer:
B
3. What type of molecule has a non-zero dipole moment?
a. An ionic compound.
b. A covalent molecule.
c. A polar molecule.
d. A molecule with polar bonds.
Answer:
C
4. Where is pi-bond electron density located?
a. Along the bond axis of two atoms.
b. Above and below the bond axis between two atoms.
c. Above and below the bond axis as well as on the bond axis between two atoms.
d. On either end of the bond axis between two atoms.
Answer:
B
5. What does a hybridized orbital denote?
a. A blending of two atomic orbitals to fit the experimentally determined shape of a
molecule.
b. A blending of the s, p, or d character of two different atoms.
c. Any mixing of s, p, or d orbital character.
d. A mixing of s, p, and/or d orbital character to fit the experimentally determined shape
of a molecule.
Answer:
D
6. What is required for sp3d hybridization to be possible?
a. There must be d orbitals present on one atom within the molecule.
b. There must be d orbitals present on the central atom of the molecule.
c. There must be at least four bonds to the central atom of the molecule.
d. There must be four or more bonds to the central atom of the molecule.
Answer:
B
7. How are pi-bonds best described by the valence bond theory?
a. As unhybridized bonds.
b. As hybridized bonds.
c. As covalent bonds.
d. As polar covalent bonds.
Answer:
A
8. What character does the pi-bonding in a double bond impart to a molecule?
a. It makes the molecule resistant to chemical reactivity.
b. It makes the double bond in the molecule resistant to lengthening or shortening.
c. It makes the double bond in the molecule resistant to twisting.
d. It makes the molecule resistant to twisting.
Answer:
C
9. For a compound to be paramagnetic, what must it possess?
a. A lone pair of electrons.
b. A double bond.
c. A double or triple bond.
d. Unpaired electrons.
Answer:
D
10. How are bonding molecular orbitals formed?
a. By the constructive interference of two molecular orbitals.
b. By the constructive interference of two atomic orbitals.
c. By the destructive interference of two atomic orbitals.
d. By the partial overlap of two or more atomic orbitals.
Answer:
B
11. How many electrons can be accommodated in an electron orbital, according to the
Pauli Exclusion Principle?
a. 1
b. 2
c. 3
d. 4
Answer:
B
12. What feature do all heteronuclear diatomic molecules share?
a. A single or double bond.
b. A non-polar bond.
c. An ionic bond.
d. A polar bond.
Answer:
D
13. What is the term for an orbital that does not contribute to nor detract from molecular
bonding?
a. A lone pair of electrons.
b. A non-bonding orbital.
c. A lone electron.
d. An inert electron pair.
Answer:
B
14. How does the delocalization of electrons in a molecule affect bonding in it, according
to molecular orbital theory?
a. It spreads the electron density over specific areas where bonding will occur.
b. It allows increased electron density at areas of lowered electron density.
c. Delocalization spreads bonding effects over the entire molecule.
d. Delocalization destabilizes the entire molecule.
Answer:
C
15. How does a p-type semiconductor move electrons through a material?
a. By conducting electrons through areas specifically doped to lessen electron density,
which appears as the movement of positive holes.
b. By conducting electrons through areas specifically doped to lessen electron density,
which appears as the movement of negative holes.
c. By conducting electrons through areas specifically doped to increase electron density,
which appears as the movement of positive holes.
d. By conducting electrons through areas specifically doped to increase electron density,
which appears as the movement of negative holes.
Answer:
A