Total number of paramagnetic species in which unpaired electron(s) is/ are present in  ${\pi }^{\ast }\mathrm{M}.\mathrm{O}.$

${\mathrm{O}}_2^{+};{\mathrm{O}}_2^{-};{\mathrm{O}}_2;{\mathrm{N}}_2^{-};{\mathrm{N}}_2^{+};{\mathrm{N}}_2^{2-};{\mathrm{B}}_2$

Total number of paramagnetic species of unpaired electron(s) is present in  ${\pi }^{\ast }\mathrm{M}.\mathrm{O}.{\mathrm{O}}_2^{+},{\mathrm{O}}_2^{-},{\mathrm{O}}_2,{\mathrm{N}}_2^{-},{\mathrm{N}}_2^{2-}$.

Like ${\mathrm{O}}_2$ molecule, sulphur (atomic number = 16) exists as ${\mathrm{S}}_2$ molecule in a vapour state and it is paramagnetic due to the presence of two unpaired electrons in antibonding π molecule orbitals.