Hard Practice — Advanced Set

Hard Practice — Chained Bonding Reasoning

Chain: steric number $\to$ hybridisation $\to$ shape (count bond + lone pairs); MOT $\to$ bond order $\to$ stability/length/magnetism; geometry $\to$ dipole moment; isoelectronic analogies.

• Bond order $=\frac{N_b-N_a}{2}$; $O_2^+(2.5)>O_2(2)>O_2^-(1.5)>O_2^{2-}(1)$.
• Lone pairs shrink angles ($CH_4>NH_3>H_2O$); symmetric molecules are non-polar.