Chapter 9, Problem 9A.1ST

Interpretation Introduction

Interpretation:

The bonding pattern of the Oxygen molecule has to be predicted.

Concept introduction:

Molecular orbital theory is a method for describing the electronic structure of molecules using quantum mechanics.

Bond order: $\text{=}\frac{{\text{N}}_{\text{b}}{\text{-N}}_{\text{a}}}{\text{2}}$

Electrons are not assigned to individual bonds between atoms, but are treated as moving under the influence of the nuclei in the whole molecule.

Explanation of Solution

The electronic configuration of oxygen $\left(\text{Z}=8\right)$ in the ground state is ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{4}}$

Each oxygen atoms has 8 electrons, hence, in ${\text{O}}_{\text{2}}$ molecule there are 16 electrons.

Therefore, the electronic configuration of ${\text{O}}_{\text{2}}$ is as follows

$\begin{array}{l}{\text{O}}_{\text{2}}{\text{:KK(σ}}_{\text{2s}}{\text{)}}^{\text{2}}{{\text{(σ}}^{\text{*}}{}_{\text{2s}}\text{)}}^{\text{2}}{{\text{(σ}}_{{\text{2p}}_{\text{z}}}\text{)}}^{\text{2}}{{\text{(π}}_{{\text{2p}}_{\text{x}}}\text{)}}^{\text{2}}{\text{=(π}}_{{\text{2p}}_{\text{y}}}{\text{)}}^{\text{2}}{{\text{(π}}^{\text{*}}{}_{{\text{2p}}_{\text{x}}}\text{)}}^{\text{1}}{\text{=(π}}_{{\text{2p}}_{\text{y}}}{\text{)}}^{\text{1}}\\ \text{here}{{\text{(σ}}_{\text{1s}}\text{)}}^{\text{2}}{{\text{(σ}}^{\text{*}}{}_{\text{1s}}\text{)}}^{\text{2}}\text{part}\text{}\text{of}\text{the}\text{configuration}\text{KK}\end{array}$

$\begin{array}{l}\text{Bond order}\text{=}\frac{{\text{N}}_{\text{b}}{\text{-N}}_{\text{a}}}{\text{2}}\\ \text{=}\frac{\text{8-4}}{\text{2}}\text{=2}\end{array}$

                    Figure -1

$\begin{array}{l}\text{Bond order}\text{=}\frac{{\text{N}}_{\text{b}}{\text{-N}}_{\text{a}}}{\text{2}}\\ \text{=}\frac{\text{8-4}}{\text{2}}\text{=2}\end{array}$

$\text{One σ}\left({\text{O}}_{\text{2}}{}_{\text{pz}}{\text{, O}}_{\text{2}}{}_{\text{pz}}\right)\text{ bond and one π}\left({\text{O}}_{\text{2}}{}_{\text{px}}{\text{, O}}_{\text{2}}{}_{\text{px}}\right)$ bond.