M.O. Electronic configuration.
O2=σ1s2<σ∗1s2<σ2s2<σ∗2s2<σ2pz2<π2py2=π2px2<π∗2py1=π∗2px1 Paramagnetic
O2−2=σ1 s 2 < σ * 1 s2 <σ2 s 2 < σ * 2 s 2 <σ2 p z 2 <π2 p y 2 =π2 p 2x < π * 2 p y 2 = π * 2 p x 2 Diamagnetic
C2=σ1s2<σ∗1s2<σ2s2<σ∗2s2<π2px2=π2py2 Diamagnetic
N2=σ1s2<σ∗1s2<σ2s2<σ∗2s2<π2px2=π2py2<σ2pz2 Diamagnetic
O2 has unpaired e− so it is paramagnetic.