d- and f-Block Elements: One-Page Formula Sheet

d- and f-Block Elements — formula sheet

Formulas

• Spin-only magnetic moment μ = √(n(n+2)) BM
• MnO₄⁻ → Mn²⁺ in acid (5 e⁻); → MnO₂ in neutral (3 e⁻)
• Cr₂O₇²⁻ → 2Cr³⁺ in acid (6 e⁻)
• Sc³⁺ and Zn²⁺ are colourless (d⁰ and d¹⁰)

Key ideas

• Variable oxidation states come from close (n−1)d and ns energies
• Colour from d–d transitions; needs unpaired d electrons
• Lanthanoid contraction makes Zr and Hf similar in size
• KMnO₄ and K₂Cr₂O₇ are strong oxidising agents

Traps to avoid

• Counting unpaired electrons wrongly for ions
• Forgetting Zn, Cd, Hg are not typical transition metals
• Wrong electrons transferred by KMnO₄ in different media

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