Bond orders and magnetic character:
O₂⁻ (BO=1.5, paramagnetic), O₂⁺ (BO=2.5, paramagnetic), O₂²⁻ (BO=1, diamagnetic);
N₂⁺ (BO=2.5, paramagnetic), N₂⁻ (BO=2.5, paramagnetic), N₂²⁻ (BO=2, diamagnetic)
1: BO 1.5 vs 2.5 (different);
2: BO 2.5 vs 2 (different);
3: BO 1.5 vs 2.5 (different);
4: O₂⁺ (BO=2.5, paramagnetic) and N₂⁻ (BO=2.5, paramagnetic) - both same bond order and paramagnetic character