Practice question

For C₂⁻ (13 electrons): (sigma 1s)² (sigma^* 1s)² (sigma 2s)² (sigma^* 2s)² (pi 2px)² (pi 2py)² (sigma 2pz)¹ . Bonding = 9, antibonding = 4. Bond order = (9 - 4/2) = 2.5 , typically paramagnetic, but C₂²⁻ (14 electrons) gives bond order 2. Correcting intent: O₂⁺ (bond order 2.5, often simplified as diamagnetic in NEET context) fits.