a
\({Li}_{2} {O} \quad \Rightarrow 2 {Li}^{+}\quad{O}^{2-}\)

\({MgO} \Rightarrow {Mg}^{2+}\quad {O}^{2-}\)

\({CaO} \quad \Rightarrow {Ca}^{2+} \quad {O}^{2-}\)

\({K}_{2} {O} \Rightarrow 2 {~K}^{+} \quad{O}^{2-}\)

\({Na}_{2} {O}_{2} \Rightarrow 2 {Na}^{+} \quad {O}_{2}^{2-}\)

\({KO}_{2} \quad \Rightarrow {K}^{+} \quad {O}_{2}^{-}\)

\({O}_{2}^{-} \Rightarrow\) Complete octet, diamagnetic

\({O}^{2} \Rightarrow \sigma_{1 {~s}}^{2} \sigma_{1 {~s}}^{* 2} \sigma_{2 {~s}}^{2} \sigma_{2 {~s}}^{*_{2}} \sigma_{2 {px}}^{2} \pi_{2 {py}}^{2} \simeq \pi_{2 {pz}}^{2} \pi_{2 {py}}^{*_{2}} \simeq \pi_{2 {pz}}^{*_{2}}({dia})\)

\({O}_{2}^{-} \Rightarrow \sigma_{1 {~s}}^{2} \sigma_{1 {~s}}^{*_{2}} \sigma_{2 {~s}}^{2} \sigma_{2 {~s}}^{* 2} \sigma_{2 {px}}^{2} \pi_{2 {py}}^{2} \simeq \pi_{2 {p} z}^{2} \pi_{2 {py}}^{*} \simeq \pi_{2 {pz}}^{* 1}({para})\)