Bonding in which of the following diatomic molecules becomes stronger by removal of an electron? (A) NO (B) N2 (C) O2…

🧠 Removing an electron increases bond order only if the electron is removed from an antibonding MO. Identify where the HOMO (highest occupied MO) sits for each species.

| Species | HOMO type | BO after removal | BO increases? | |---|---|---|---| | NO (2.5) | $\pi^*_{2p}$ (antibonding) | $\ce{NO+}$: 3 | ✓ | | $\ce{N2}$ (3) | $\sigma_{2p}$ (bonding) | $\ce{N2+}$: 2.5 | ✗ | | $\ce{O2}$ (2) | $\pi^*_{2p}$ (antibonding) | $\ce{O2+}$: 2.5 | ✓ | | $\ce{C2}$ (2) | $\pi_{2p}$ (bonding) | $\ce{C2+}$: 1.5 | ✗ | | $\ce{B2}$ (1) | $\pi_{2p}$ (bonding) | $\ce{B2+}$: 0.5 | ✗ |

⚡ Key rule: if the HOMO is an antibonding MO, removing an electron increases BO and strengthens the bond.

$\boxed{\text{Answer: (c) A and C only (NO and } \ce{O2}\text{)}}$