Which of the following pairs have the first element exhibiting a strictly LOWER first ionization pot — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

This explores standard period anomalies. $O < N$ (N is half-filled $2p^3$), $S < P$ (P is half-filled $3p^3$), $B < Be$ (Be is full $2s^2$, highly penetrating), and $Al < Mg$ (Mg is full $3s^2$). All given pairs are true exceptions to the general left-to-right increase.