Hard Practice — Advanced Set

Hard Practice — Chained d-/f-Block Reasoning

Chain: ion $\to$ d-count $\to$ unpaired electrons $\to$ $\mu$; redox electron-count in permanganate/dichromate; colour from d-d transitions; lanthanoid contraction consequences.

• $\mu=\sqrt{n(n+2)}$ BM; $MnO_4^-$ gains 5 e (acidic), $Cr_2O_7^{2-}$ gains 6 e.
• $d^0$/$d^{10}$ ions are colourless; high enthalpy of atomisation comes from unpaired d-electrons.