Medium Practice — Set 1

Quick Recap — Ordering & Anomalies

• Period-2 IE$_1$ (kJ/mol): Li 520, Be 899, B 801, C 1086, N 1402, O 1314, F 1681, Ne 2081 — note Be $>$ B and N $>$ O (stable $2s^2$ / half-filled $2p^3$).
• Isoelectronic radius: $N^{3-}>O^{2-}>F^->Na^+>Mg^{2+}>Al^{3+}$.
• Electron gain enthalpy (most negative): Cl $>$ F $>$ Br $>$ I.
• Electronegativity (period 2): F $>$ O $>$ N $>$ C.