Question 1

According to molecular orbital (MO)  theory, the twelve outermost electrons in the O2 molecule are distributed as follows:

Accepted Answer

A)  12 in bonding MOs, 0 in antibonding MOs.
B)  10 in bonding MOs, 2 in antibonding MOs.
C)  9 in bonding MOs, 3 in antibonding MOs.
D)  8 in bonding MOs, 4 in antibonding MOs.
E)  7 in bonding MOs, 5 in antibonding MOs.F) B) and C)
G) A) and C)

Question 2

When PCl5 solidifies it forms PCl4+ cations and PCl6-anions. According to valence bond theory, what hybrid orbitals are used by phosphorus in the PCl4+ cations?

Accepted Answer

A)  sp
B)  sp 2
C)  sp 3
D)  sp 3 d
E)  sp 3 d 2F) B) and E)
G) All of the above

Question 3

According to molecular orbital theory, all diatomic molecules with an even number of electrons will be diamagnetic.

Accepted Answer

A) True 
 B)False

Question 4

A molecule with the formula AX3 uses __________ to form its bonds.

Accepted Answer

A)  sp hybrid orbitals
B)  sp 2 hybrid orbitals
C)  sp 3 hybrid orbitals
D)  sp 3 d hybrid orbitals
E)  sp 3 d 2 hybrid orbitalsF) D) and E)
G) A) and B)

Question 5

Atoms of period 3 and beyond can undergo sp3d2 hybridization, but atoms of period 2 cannot.

Accepted Answer

A) True 
 B)False

Question 6

Which one of the following statements about orbital hybridization is incorrect?

Accepted Answer

A)  The carbon atom in CH4 is sp 3 hybridized.
B)  The carbon atom in CO 2 is sp hybridized.
C)  The nitrogen atom in NH 3 is sp 2 hybridized.
D)  sp 2 hybrid orbitals are coplanar, and at 120° to each other.
E)  sp hybrid orbitals lie at 180° to each other.F) None of the above
G) A) and D)

Question 7

In applying molecular orbital theory, the bond order is calculated in the same way as with Lewis structures.

Accepted Answer

A) True 
 B)False

Question 8

A carbon-carbon double bond in a molecule may give rise to the existence of cis and trans isomers.

Accepted Answer

A) True 
 B)False

Question 9

According to the molecular orbital (MO)  treatment of the NO molecule, what are the bond order and the number of unpaired electrons, respectively?

Accepted Answer

A)  2, 2
B)  3, 3
C)  1, 1
D)  1.5, 2
E)  2.5, 1F) A) and B)
G) A) and C)

Question 10

According to valence bond theory, the triple bond in ethyne (acetylene, C2H2)  consists of

Accepted Answer

A)  three σ bonds and no π bonds.
B)  two σ bonds and one π  bond.
C)  one σ bond and twoπ bonds.
D)  no σ bonds and three π  bonds.
E)  None of these choices are correct.F) A) and C)
G) A) and E) C

Question 11

The angles between sp2 hybrid orbitals are 109.5°.

Accepted Answer

A) True 
 B)False

Question 12

According to molecular orbital theory, what is the bond order in the O2+ ion?

Accepted Answer

A)  5.5
B)  5
C)  4
D)  2.5
E)  1.5F) A) and B)
G) All of the above

Question 13

Carbon uses __________ hybrid orbitals in ClCN.

Accepted Answer

A)  sp
B)  sp 2
C)  sp 3
D)  sp 3 d
E)  sp 3 d 2F) B) and C)
G) A) and C)

Question 14

Determine the shape (geometry)  of PCl3 and then decide on the appropriate hybridization of phosphorus in this molecule. (Phosphorus is the central atom.)

Accepted Answer

A)  sp 3
B)  sp 2
C)  sp
D)  sp 3 d
E)  sp 3 d 2F) A) and E)
G) None of the above

Question 15

Valence bond theory predicts that carbon will use __________ hybrid orbitals in the carbonate anion, CO3−.

Accepted Answer

A)  sp
B)  sp 2
C)  sp 3
D)  sp 3 d
E)  sp 3 d 2F) C) and D)
G) B) and C) B

Question 16

A carbon-carbon triple bond in a molecule may give rise to the existence of cis and trans isomers.

Accepted Answer

A) True 
 B)False  False

Question 17

According to valence bond theory, overlap of bonding orbitals of atoms will weaken a bond, due to electron-electron repulsion.

Accepted Answer

A) True 
 B)False

Question 18

Which one, if any, of the following statements about the MO treatment of the bonding in benzene is correct?

Accepted Answer

A)  MO theory uses resonance to describe the delocalized nature of the bonding in benzene.
B)  The lowest energy pi-bonding orbital in benzene can hold up to 6 electrons.
C)  MO theory predicts that benzene should be paramagnetic.
D)  The lowest energy pi-bonding MO in benzene has two hexagonal lobes, above and below the plane of the carbon atoms.
E)  None of these choices are correct.F) B) and D)
G) A) and B)

Question 19

A molecule with the formula AX4E uses __________ to form its bonds.

Accepted Answer

A)  sp 2 hybrid orbitals
B)  sp 3 hybrid orbitals
C)  sp 3 d hybrid orbitals
D)  sp 3 d 2 hybrid orbitals
E)  None of these choices are correct.F) B) and C)
G) None of the above

Question 20

Valence bond theory predicts that tin will use __________ hybrid orbitals in SnF5−.

Accepted Answer

A)  sp 2
B)  sp 3
C)  sp 3 d
D)  sp 3 d 2
E)  d 2 sp 3F) B) and E)
G) D) and E)

Exam 11: Theories of Covalent Bonding

According to molecular orbital (MO) theory, the twelve outermost electrons in the O2 molecule are distributed as follows:

Correct AnswerverifiedShow Answer

When PCl5 solidifies it forms PCl4+ cations and PCl6-anions. According to valence bond theory, what hybrid orbitals are used by phosphorus in the PCl4+ cations?

Correct AnswerverifiedShow Answer

According to molecular orbital theory, all diatomic molecules with an even number of electrons will be diamagnetic.

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A molecule with the formula AX3 uses __________ to form its bonds.

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Atoms of period 3 and beyond can undergo sp3d2 hybridization, but atoms of period 2 cannot.

Correct AnswerverifiedShow Answer

Which one of the following statements about orbital hybridization is incorrect?

Correct AnswerverifiedShow Answer

In applying molecular orbital theory, the bond order is calculated in the same way as with Lewis structures.

Correct AnswerverifiedShow Answer

A carbon-carbon double bond in a molecule may give rise to the existence of cis and trans isomers.

Correct AnswerverifiedShow Answer

According to the molecular orbital (MO) treatment of the NO molecule, what are the bond order and the number of unpaired electrons, respectively?

Correct AnswerverifiedShow Answer

According to valence bond theory, the triple bond in ethyne (acetylene, C2H2) consists of

Correct AnswerverifiedC

The angles between sp2 hybrid orbitals are 109.5°.

Correct AnswerverifiedShow Answer

According to molecular orbital theory, what is the bond order in the O2+ ion?

Correct AnswerverifiedShow Answer

Carbon uses __________ hybrid orbitals in ClCN.

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Determine the shape (geometry) of PCl3 and then decide on the appropriate hybridization of phosphorus in this molecule. (Phosphorus is the central atom.)

Correct AnswerverifiedShow Answer

Valence bond theory predicts that carbon will use __________ hybrid orbitals in the carbonate anion, CO3−.

Correct AnswerverifiedB

A carbon-carbon triple bond in a molecule may give rise to the existence of cis and trans isomers.

Correct AnswerverifiedFalse

According to valence bond theory, overlap of bonding orbitals of atoms will weaken a bond, due to electron-electron repulsion.

Correct AnswerverifiedShow Answer

Which one, if any, of the following statements about the MO treatment of the bonding in benzene is correct?

Correct AnswerverifiedShow Answer

A molecule with the formula AX4E uses __________ to form its bonds.

Correct AnswerverifiedShow Answer

Valence bond theory predicts that tin will use __________ hybrid orbitals in SnF5−.

Correct AnswerverifiedShow Answer

According to molecular orbital (MO) theory, the twelve outermost electrons in the O₂ molecule are distributed as follows:

Correct Answer
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When PCl₅solidifies it forms PCl₄⁺ cations and PCl₆^-anions. According to valence bond theory, what hybrid orbitals are used by phosphorus in the PCl₄⁺ cations?

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A molecule with the formula AX₃ uses __________ to form its bonds.

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Atoms of period 3 and beyond can undergo sp³d² hybridization, but atoms of period 2 cannot.

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According to valence bond theory, the triple bond in ethyne (acetylene, C₂H₂) consists of

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C

The angles between sp² hybrid orbitals are 109.5°.

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According to molecular orbital theory, what is the bond order in the O₂⁺ ion?

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Determine the shape (geometry) of PCl₃ and then decide on the appropriate hybridization of phosphorus in this molecule. (Phosphorus is the central atom.)

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Valence bond theory predicts that carbon will use __________ hybrid orbitals in the carbonate anion, CO₃⁻.

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B

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False

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A molecule with the formula AX₄E uses __________ to form its bonds.

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Valence bond theory predicts that tin will use __________ hybrid orbitals in SnF₅⁻.

Correct Answer
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