The total number of electrons in all bonding molecular orbitals of  ${\mathrm{O}}_2^{-2}$  is ____

O₂⁻²
σ1s²,σ∗1s²,σ2s²,σ∗2s²,σ2p²z,π2p²x=π2p²y,π∗2p²x=π∗2p²y
Total number of electrons in bonding molecular orbitals is =10