Why does Zn²⁺ have no color (Zn = d¹⁰)?
ANo d-d transition possible — d sub-shell full
BReflects all light
CMass
DRandom
Answer & Solution
Correct answer: A. No d-d transition possible — d sub-shell full
Zn²⁺: 3d¹⁰. No empty d orbital to receive a promoted electron. So no d-d transition in visible. Hence Zn²⁺ salts are colorless. Same for Sc³⁺ (d⁰), Cu⁺ (d¹⁰).
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