Chapter 9, Problem 9.14P

(a)

Interpretation Introduction

Interpretation:

The stability of the given configuration (a) has to be given.

Concept Introduction:

The bond order can be calculated as,

Bond order $\text{=}\frac{\left({\text{N}}_{\text{b}}\right)\text{-}\left({\text{N}}_{\text{a}}\right)}{\text{2}}$

Where, ${\text{N}}_{\text{b}}$ is number of electrons in bonding orbital.

${\text{N}}_{\text{a}}$ is number of electrons in antibonding orbital

Explanation of Solution

The given configuration is,

  ${\left(\text{σ1s}\right)}^{\text{2}}{\left({\text{σ}}^{\text{*}}\text{1s}\right)}^{\text{2}}{\left(\text{π2p}\right)}^{\text{1}}$

There are 3 electrons in the bonding and two electrons in the antibonding orbitals.

The bond order can be calculated as,

Bond order $\text{=}\frac{\left({\text{N}}_{\text{b}}\right)\text{-}\left({\text{N}}_{\text{a}}\right)}{\text{2}}$

Bond order $\begin{array}{l}\text{=}\frac{\left(\text{3}\right)\text{-}\left(\text{2}\right)}{\text{2}}\\ \text{=0}\text{.5}\end{array}$

The bond order is 0.5, which is stable configuration.  There is no dissociation of excited molecules.

(b)

Interpretation Introduction

Interpretation:

The stability of the given (b) configuration has to be given.

Concept Introduction:

Refer to part (a).

Explanation of Solution

The given configuration is,

${\left(\text{σ1s}\right)}^{\text{2}}{\left({\text{σ}}^{\text{*}}\text{1s}\right)}^{\text{2}}{\left(\text{σ2s}\right)}^{\text{1}}{\left({\text{σ}}^{\text{*}}\text{2s}\right)}^{\text{1}}$

There are 3 electrons in the bonding and 3 electrons in the antibonding orbitas.

The bond order can be calculated as,

Bond order $\text{=}\frac{\left({\text{N}}_{\text{b}}\right)\text{-}\left({\text{N}}_{\text{a}}\right)}{\text{2}}$

Bond order $\begin{array}{l}\text{=}\frac{\left(\text{3}\right)\text{-}\left(3\right)}{\text{2}}\\ \text{=0}\end{array}$

The bond order is 0 which is unstable configuration.  It would results in the dissociation of molecule.

(c)

Interpretation Introduction

Interpretation:

The stability of the given (c) configuration has to be given.

Concept Introduction:

Refer to part (a).

Explanation of Solution

The given configuration is,

  ${\left(\text{σ1s}\right)}^{\text{2}}{\left({\text{σ}}^{\text{*}}\text{1s}\right)}^{\text{2}}{\left(\text{σ2s}\right)}^{\text{2}}{\left({\text{σ}}^{\text{*}}\text{2s}\right)}^{\text{2}}{\left(\text{π2p}\right)}^{\text{4}}{\left({\text{π}}^{\text{*}}\text{2p}\right)}^{\text{1}}$.

There are 8 electrons in the bonding orbital and 5 electrons in the antibonding orbital.

The bond order can be calculated as,

Bond order $\text{=}\frac{\left({\text{N}}_{\text{b}}\right)\text{-}\left({\text{N}}_{\text{a}}\right)}{\text{2}}$

Bond order $\begin{array}{l}\text{=}\frac{\left(8\right)\text{-}\left(5\right)}{\text{2}}\\ \text{=1}\text{.5}\end{array}$

The bond order is 1.5, which is stable configuration, and there would no dissociation of excited molecules.

(d)

Interpretation Introduction

Interpretation:

The stability of the given (d) configuration has to be given.

Concept Introduction:

Refer to part (a).

Explanation of Solution

The given configuration is,

  ${\left(\text{σ1s}\right)}^{\text{2}}{\left({\text{σ}}^{\text{*}}\text{1s}\right)}^{\text{2}}{\left(\text{σ2s}\right)}^{\text{2}}{\left({\text{σ}}^{\text{*}}\text{2s}\right)}^{\text{2}}{\left(\text{π2p}\right)}^{\text{4}}{\left({\text{π}}^{\text{*}}\text{2p}\right)}^{\text{4}}{\left({\text{σ}}^{\text{*}}\text{2p}\right)}^{\text{1}}$

There are 8 electrons in the bonding and nine electrons in the antibonding orbitals.

The bond order can be calculated as,

Bond order $\text{=}\frac{\left({\text{N}}_{\text{b}}\right)\text{-}\left({\text{N}}_{\text{a}}\right)}{\text{2}}$

Bond order $\begin{array}{l}\text{=}\frac{\left(8\right)\text{-}\left(9\right)}{\text{2}}\\ \text{=-0}\text{.5}\end{array}$

The bond order is -0.5 which is unstable configuration.  It would results in the dissociation of the molecule.