${O}_{2}^{+} \rightarrow \sigma_{1 {~s}}^{2}<\sigma_{1 {~s}}^{*}<\sigma_{2 {~s}}^{2}<\sigma_{2 {~s}}^{*}<\sigma_{2 {pz}}^{2}<\pi_{2 {px}}^{2}=\pi_{2 {py}}^{2}<\pi_{2 {px}}^{*}=\pi_{2 {py}}^{*}$

unpaired ${e}^{-}=1 \ldots \mu=1.73\, {BM}$

$(1)$ ${Cu}^{+} {I}^{-} {Cu}+\rightarrow[{Ar}] 3 {~d}^{10} \therefore$ unpaired ${e}^{-}=0$

${I}^{-} \rightarrow[{Xe}] \therefore$ unpaired ${e}^{-}=0$

therefore $\mu=0$

$3.$ $\left[{Cu}\left({NH}_{3}\right)_{4}\right] {Cl}_{2}$

${Cu} \rightarrow[{A}] 3 {~d}^{3} \therefore$ unpaired $=1 \quad \therefore \mu=1.73 \,{BM}$

$4.$ ${O}_{2}^{-} \rightarrow {d}$

$\sigma_{1 {~s}}^{2}<\sigma_{1 {~s}}^{* 2}<\sigma_{2 {~s}}^{2}<\sigma_{2 {~s}}^{* 2}<\sigma_{2 {px}}^{2}<\pi_{2 {px}}^{2}=\pi_{2 {py}}^{2}<\pi_{2 {px}}^{*_{1}}=\pi_{2 {py}}^{*}$

$\left(11 {e}^{-}\right)$

$\therefore$ unpaired $\quad \therefore \mu=1.73\, {BM}$