Medium Practice — Set 2

Quick Recap — MOT, Bond Order & Reasoning

• MOT filling ($\le N_2$): $\sigma1s,\sigma^*1s,\sigma2s,\sigma^*2s,\pi2p_x=\pi2p_y,\sigma2p_z,\pi^*,\sigma^*$; for $O_2,F_2$ the $\sigma2p_z$ drops below the $\pi2p$.
• Bond order/stability: $N_2(3)>O_2(2)>F_2(1)$; ions $O_2^+(2.5)$, $O_2^-(1.5)$, $O_2^{2-}(1)$.
• Magnetism: unpaired electrons $\Rightarrow$ paramagnetic ($O_2$, $B_2$); paired $\Rightarrow$ diamagnetic ($N_2$, $C_2$, $F_2$).
• Back-bonding, resonance and Fajans' rules modify bond character and strength.