See image — AITS & Test Series Chemistry Question

💡 Solution & Explanation

Ionization potential is amount of energy required to take out most loosely bonded electron from neutral atom. Its value depends on stability of atom. (electronic configuration) 2 2 2 2 2 3 2 2 4 2 2 5 C 1s 2s 2p N 1s 2s 2p O 1s 2s 2p F 1s 2s 2p     2 2 1 2 2 2 2 2 3 2 2 4 C 1s 2s 2p N 1s 2s 2p O 1s 2s 2p F 1s 2s 2p         As for IE2 the electron in all the cases is to be removed from 2p orbital so it must follow the order C N O F    (i.e. increase across a period) But in case of O+, the 2p orbital is half-filled and is more stable as compared to others. So the order becomes:C N F O or O F N C      