Question 1

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

Accepted Answer

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 $\sigma$ or  $\pi$ 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. 
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 $\sigma$ or  $\pi$ 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 2

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

Accepted Answer

A)  sp 
B)  sp2 
C)  sp3 
D)  sp3d 
E)  sp3d2 
A)  sp 
B)  sp2 
C)  sp3 
D)  sp3d 
E)  sp3d2

Question 3

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

Question 4

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

Accepted Answer

A)  three $\sigma$ bonds and no  $\pi$ bonds. 
B)  two $\sigma$bonds and one  $\pi$ bond. 
C)  one $\sigma$ bond and two  $\pi$ bonds. 
D)  no$\sigma$ bonds and three  $\pi$ bonds. 
E)  None of these choices is correct. 
A)  three $\sigma$ bonds and no  $\pi$ bonds. 
B)  two $\sigma$bonds and one  $\pi$ bond. 
C)  one $\sigma$ bond and two  $\pi$ bonds. 
D)  no$\sigma$ bonds and three  $\pi$ bonds. 
E)  None of these choices is correct.

Question 5

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

Accepted Answer

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

Question 6

In one sentence, state how molecular orbitals are usually obtained.

Accepted Answer

By the linear combin

Question 7

The angles between sp2 hybrid orbitals are 109.5 $\degree$.

Accepted Answer

A) True 
 B)False

Question 8

In molecular orbital theory, combination of two 2p atomic orbitals may give rise to either $\sigma$ or $\pi$ type molecular orbitals.

Accepted Answer

A) True 
 B)False

Question 9

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

Accepted Answer

A)  sp hybrid orbitals 
B)  sp2 hybrid orbitals 
C)  sp3 hybrid orbitals 
D)  sp3d hybrid orbitals 
E)  sp3d2 hybrid orbitals 
A)  sp hybrid orbitals 
B)  sp2 hybrid orbitals 
C)  sp3 hybrid orbitals 
D)  sp3d hybrid orbitals 
E)  sp3d2 hybrid orbitals

Question 10

Explain what is meant by a node (or nodal plane) in a molecular orbital and draw sketches of the following orbitals, indicating at least one nodal plane in each one.
A) a $\sigma$* orbital
B) a  $\pi$* orbital

Accepted Answer

A nodal plane is a p

Question 11

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

Accepted Answer

A)  sp 
B)  sp2 
C)  sp3 
D)  sp3d 
E)  sp3d2 
A)  sp 
B)  sp2 
C)  sp3 
D)  sp3d 
E)  sp3d2

Question 12

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

Accepted Answer

A) True 
 B)False

Question 13

Explain what is meant by the term "bond order" and describe how it can be calculated using the information in a molecular orbital energy level diagram.

Accepted Answer

The bond order in MO theory is the net n

Question 14

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 15

Overlap of two sp2 hybrid orbitals produces a  $\pi$ bond.

Accepted Answer

A) True 
 B)False

Question 16

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

Accepted Answer

A)  C2H2 C is the central atom 
B)  C2H4, C is the central atom 
C)  C2H6, C is the central atom 
D)  CO2, C is the central atom 
E)  H2O, O is the central atom 
A)  C2H2 C is the central atom 
B)  C2H4, C is the central atom 
C)  C2H6, C is the central atom 
D)  CO2, C is the central atom 
E)  H2O, O is the central atom

Question 17

Valence bond theory predicts that tin will use _____ hybrid orbitals in SnCl3¯.

Accepted Answer

A)  sp 
B)  sp2 
C)  sp3 
D)  sp3d 
E)  sp3d2 
A)  sp 
B)  sp2 
C)  sp3 
D)  sp3d 
E)  sp3d2

Question 18

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

Question 19

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

Accepted Answer

A) True 
 B)False

Question 20

Sketch the shapes of the $\sigma$1s and $\sigma$1s* molecular orbitals formed by the overlap of two hydrogen 1s atomic orbitals.

Accepted Answer

Exam 11: Theories of Covalent Bonding

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

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

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

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

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

In one sentence, state how molecular orbitals are usually obtained.

The angles between sp2 hybrid orbitals are 109.5 °\degree° .

In molecular orbital theory, combination of two 2p atomic orbitals may give rise to either σ\sigmaσ or π\piπ type molecular orbitals.

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

Explain what is meant by a node (or nodal plane) in a molecular orbital and draw sketches of the following orbitals, indicating at least one nodal plane in each one. A) a σ\sigmaσ * orbital B) a π\piπ * orbital

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

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

Explain what is meant by the term "bond order" and describe how it can be calculated using the information in a molecular orbital energy level diagram.

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

Overlap of two sp2 hybrid orbitals produces a π\piπ bond.

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

Valence bond theory predicts that tin will use _____ hybrid orbitals in SnCl3¯.

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

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

Sketch the shapes of the σ\sigmaσ 1s and σ\sigmaσ 1s* molecular orbitals formed by the overlap of two hydrogen 1s atomic orbitals.

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry: Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

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

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

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

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

The angles between sp² hybrid orbitals are 109.5 $\degree$ .

In molecular orbital theory, combination of two 2p atomic orbitals may give rise to either $\sigma$ or $\pi$ type molecular orbitals.

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

Explain what is meant by a node (or nodal plane) in a molecular orbital and draw sketches of the following orbitals, indicating at least one nodal plane in each one. A) a $\sigma$ * orbital B) a $\pi$ * orbital

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

Overlap of two sp² hybrid orbitals produces a $\pi$ bond.

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

Valence bond theory predicts that tin will use _____ hybrid orbitals in SnCl₃^¯.

Sketch the shapes of the $\sigma$ ₁_s and $\sigma$ ₁_s* molecular orbitals formed by the overlap of two hydrogen 1s atomic orbitals.