Why is the second ionization enthalpy () of Oxygen strictly greater than the second ionization entha — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

The first $IE$ of N is higher than O due to N's half-filled $2p^3$ state. However, after removing one electron, the $O^+$ ion now possesses the half-filled $2p^3$ configuration, making its second electron extremely difficult to remove compared to the $N^+$ ion (which is $2p^2$). Thus, $IE_2(O) > IE_2(N)$.