Question

A Lewis structure obeying the octet rule can be drawn for ${\mathit{O}}_{\mathbf{2}}$as follows:

Use the molecular orbital energy-level diagram for ${\mathit{O}}_{\mathbf{2}}$to show that the above Lewis structure corresponds to an exicted state.

Short answer

The molecular orbital diagram is in complete accordance with the Lewis structure of $O_2$molecule.

Step-by-step solution

Step 1- Molecular orbital diagaram

The molecular orbital energy-level diagram for $O_2$.

Step 2- Correspondence between Lewis structure and molecular orbital diagram 

The molecular orbital theory completely supports the Lewis structure. As shown in the molecular orbital theory there are two lone pairs of electrons.

$$\begin{gathered} Bond Order=\frac{Number of bonding electrons - Number of antibonding electrons}{2} \\ BondOrder=\frac{6-2}{2} \\ BondOrder=2 \end{gathered}$$

The calculated bond order is same as that shown in the Lewis structure.