Chapter 9.7, Problem 1PPC

Interpretation Introduction

Interpretation:

The homonuclear diatomic molecules in which addition and removal of electrons have the same effect on the bond order are to be identified and the reason for this effect is to be explained.

Concept introduction:

Two atomic orbitals combine in order to form one bonding and one antibonding molecular orbital. The orbitals that lie on internuclear axis combine to form $\sigma$

(sigma) molecular orbital, and the orbitals parallel to each other combine to form $\pi$ molecular orbitals.

The molecular orbital formed by the combination of $\text{1s}$

orbital forms bonding molecular orbital designated as ${\sigma }_{1s}$ and antibonding molecular orbital, ${\sigma }^{\ast }{}_{1s}$. The $\text{2}s$

orbital forms corresponding molecular orbitals.

Molecular orbital formed by the combination of $2p_x$

orbital forms a bonding molecular orbital designated as ${\sigma }_{2p_{\text{x}}}$

and an antibonding molecular orbital designated as ${\sigma }^{\ast }{}_{2p_{\text{x}}}$.

Molecular orbitals formed by the combining of $2p_{\text{y}}$ and $2p_{\text{z}}$

orbitals form bonding molecular orbitals designated as ${\text{π}}_{\text{2}{p}_{\text{y}}}$

and ${\text{π}}_{\text{2}{p}_{\text{z}}}$

and antibonding molecular orbitals designated as ${\text{π}}^{\ast }{}_{\text{2}{p}_{\text{y}}}$

and ${\text{π}}^{\ast }{}_{\text{2}{p}_{\text{z}}}$.

Bond order is determined by subtracting the number of electrons present in the antibonding orbitals from the number of electrons present in the bonding orbitals and dividing by two.