The d- and f-Block Elements Class 12 Chemistry Notes – Formulas & Quick Revision

d- and f-Block mein transition elements ke properties, KMnO₄/K₂Cr₂O₇ aur lanthanoid contraction aate hain. Yahan aapko is chapter ke sabse important formulas aur quick revision points free milte hain — NCERT/CBSE syllabus ke hisaab se, boards aur JEE/NEET dono ke liye.

Important Formulas & Concepts — The d- and f-Block Elements

• Transition elements: incomplete d-orbital (Zn, Cd, Hg exceptions)
• Magnetic moment: μ = √[n(n+2)] BM (n = unpaired electrons)
• Colour: d-d transition se
• Variable oxidation states: Mn +2 to +7
• K₂Cr₂O₇: Cr₂O₇²⁻ + 14H⁺ + 6e⁻ → 2Cr³⁺ + 7H₂O (orange → green)
• KMnO₄ acidic: MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O (purple → colourless)
• Lanthanoid contraction: 4f poor shielding se size ghatta hai
• Zr-Hf same size (lanthanoid contraction ka result)

Quick Revision Points

• Zn²⁺, Sc³⁺ colourless (d⁰/d¹⁰); Cu²⁺ blue, Mn²⁺ pink
• Transition metals ache catalysts hain (variable OS + surface)
• Cr aur Cu ke configurations exceptional
• Interstitial compounds aur alloys banana transition metals ki khasiyat
• Actinoids mein OS ki range zyada hoti hai

FAQ

KMnO₄/K₂Cr₂O₇ ki equations rate karna zaroori hai?

Haan — preparation + oxidising reactions boards mein pakke hain. PDF mein reaction map hai.

Magnetic moment numericals?

Configuration se n nikaalo, formula lagao — PDF mein ions ki ready table hai.

Explore more: free sample notes, free calculators aur interactive simulators.