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Why is Sc^(3+) colourless ?...

Why is `Sc^(3+)` colourless ?

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The electronic configuration of `._(21)Sc1s^(2)2s^(2)2p^(6)a3s^(2)3p^(6)3d^(1)4s^(2) or [ar]3d^(1)4s^(2) and Sc^(3+)[Ar]d^(0).`
(2) Since there are no unpaired electrons in 3d-subshell, `drarrd` transition is not possible.
(3) Therefore, `Sc^(3+)` ions do not absorb the radiations in the visible region. Hence salts of `Sc^(3+)` are colourless (or white).
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