Deck 11: Theories of Covalent Bonding

Question 1

A molecule with the formula AX₄ uses __________ to form its bonds.

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 orbitals

Answer 1

sp ³ hybrid orbitals

Question 2

In molecular orbital theory, combination of two 2p atomic orbitals may give rise to either σ orπ type molecular orbitals.

Answer 2

True

Question 3

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

Answer 3

False

Question 4

In the valence bond treatment, a π bond is formed when two 2p orbitals overlap side to side.

Question 5

Overlap of two sp² hybrid orbitals produces a π bond.

Question 6

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

Question 7

In molecular orbital theory, molecules with an even number of electrons will have bond orders which are whole numbers.

Question 8

According to valence bond theory, which orbitals on N and H overlap in the NH₃ molecule?

A)2 p on N overlaps with 2 s on H
B)2 p on N overlaps with 1 s on H
C)2 s on N overlaps with 1 s on H
D)sp ³ on N overlaps with sp on H
E)sp ³ on N overlaps with 1 s on H

Question 9

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

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 orbitals

Question 10

Valence bond theory is able to explain why molecular oxygen is paramagnetic.

Question 11

Hybrid orbitals of the sp³d type occur in sets of four.

Question 12

A molecule with the formula AX₂ uses __________ to form its bonds.

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 orbitals

Question 13

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

Question 14

In molecular orbital theory, combination of two atomic orbitals produces two molecular orbitals.

Question 15

Valence bond theory explains the bonding in diatomic molecules such as HCl without resorting to the use of hybrid orbitals.

Question 16

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

Question 17

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

Question 18

The angles between sp² hybrid orbitals are 109.5°.

Question 19

In the valence bond treatment, overlap of an s orbital on one atom with an sp³ orbital on another atom can give rise to a σ bond.

Question 20

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

Question 21

Valence bond theory predicts that xenon will use __________ hybrid orbitals in XeOF₄.

A)sp
B)sp ²
C)sp ³
D)sp ³ d
E)sp ³ d ²

Question 22

A molecule with the formula AX₃E uses __________ to form its bonds.

A)s and p atomic orbitals
B)sp ³ hybrid orbitals
C)sp ² hybrid orbitals
D)sp hybrid orbitals
E)sp ³ d ² hybrid orbitals

Question 23

For which one of the following molecules is the indicated type of hybridization not appropriate for the central atom?

A)BeCl ₂ sp ²
B)SiH ₄ sp ³
C)BF ₃ sp ²
D)C ₂H ₂ sp
E)H ₂O sp ³

Question 24

Carbon uses __________ hybrid orbitals in ClCN.

A)sp
B)sp ²
C)sp ³
D)sp ³ d
E)sp ³ d ²

Question 25

According to valence bond theory, which of the following molecules involves sp² hybridization of orbitals on the central atom? (central atom is bold)

A)C ₂H ₂
B)C ₂H ₄
C)C ₂H ₆
D)CO ₂
E)H ₂ O

Question 26

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

A)sp
B)sp ²
C)sp ³
D)sp ³ d
E)sp ³ d ²

Question 27

Valence bond theory predicts that bromine will use __________ hybrid orbitals in BrF₅.

A)sp ²
B)sp ³
C)sp ³ d
D)sp ³ d ²
E)None of these choices are correct.

Question 28

Valence bond theory predicts that iodine will use __________ hybrid orbitals in ICl₂⁻.

A)sp ²
B)sp ³
C)sp ³ d
D)sp ³ d ²
E)None of these choices are correct.

Question 29

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?

A)sp
B)sp ²
C)sp ³
D)sp ³ d
E)sp ³ d ²

Question 30

Valence bond theory predicts that tin will use __________ hybrid orbitals in SnCl₃⁻.

A)sp
B)sp ²
C)sp ³
D)sp ³ d
E)sp ³ d ²

Question 31

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

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.

Question 32

Select the correct statement aboutπ - bonds in valence bond theory.

A)A π bond is stronger than a sigma bond.
B)A π bond can hold 4 electrons, two above and two below the σ-bond axis.
C)A carbon-carbon double bond consists of twoπ bonds.
D)A π bond is the same strength as a σ bond.
E)A π bond between two carbon atoms restricts rotation about the C-C axis.

Question 33

Valence bond theory predicts that bromine will use __________ hybrid orbitals in BrF₃.

A)sp ²
B)sp ³
C)sp ³ d
D)sp ⁴
E)sp ³ d ²

Question 34

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

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.

Question 35

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

A)sp ³
B)sp ²
C)sp
D)sp ³ d
E)sp ³ d ²

Question 36

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

A)sp ²
B)sp ³
C)sp ³ d
D)sp ³ d ²
E)d ² sp ³

Question 37

How many sigma and pi bonds, respectively, are in the molecule below? CH₃CH₂CHCHCH₃

A)16, 1
B)16, 0
C)15, 1
D)15, 0
E)14, 1

Question 38

Valence bond theory predicts that sulfur will use __________ hybrid orbitals in sulfur dioxide, SO₂.

A)sp
B)sp ²
C)sp ³
D)sp ³ d
E)sp ³ d ²

Question 39

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

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.

Question 40

A molecule with the formula AX₄E₂ uses __________ to form its bonds.

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 orbitals

Question 41

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

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

Question 42

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

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.

Question 43

The lone pair of electrons on sulfur in the sulfite ion (SO₃²⁻) is in

A)a p orbital.
B)an s orbital.
C)an sp ² hybrid orbital.
D)an sp ³ hybrid orbital.
E)none of these orbital types.

Question 44

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

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.

Question 45

The nitrosonium ion, NO⁺, forms a number of interesting complexes with nickel, cobalt, and iron. According to molecular orbital theory, which of the following statements about NO⁺ is correct?

A)NO ⁺ has a bond order of 2 and is paramagnetic.
B)NO ⁺ has a bond order of 2 and is diamagnetic.
C)NO ⁺ has a bond order of 3 and is paramagnetic.
D)NO ⁺ has a bond order of 3 and is diamagnetic.
E)None of these choices are correct.

Question 46

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

A)5.5
B)5
C)4
D)2.5
E)1.5

Question 47

Which of the following statements relating to molecular orbital (MO) theory is incorrect?

A)Combination of two atomic orbitals produces one bonding and one antibonding MO.
B)A bonding MO is lower in energy than the two atomic orbitals from which it is formed.
C)Combination of two 2p orbitals may result in either σ orπ MOs.
D)A species with a bond order of zero will not be stable.
E)In a stable molecule having an even number of electrons, all electrons must be paired.

Question 48

One can safely assume that the 3s- and 3p-orbitals will form molecular orbitals similar to those formed when 2s- and 2p-orbitals interact. According to molecular orbital theory, what will be the bond order for the Cl₂⁺ ion?

A)0.5
B)1
C)1.5
D)2
E)None of these choices are correct.