MCQ
The aqueous solution containing which one of the following ions will be colourless
  • $S{c^{3 + }}$
  • B
    $F{e^{2 + }}$
  • C
    $T{i^{3 + }}$
  • D
    $M{n^{2 + }}$ (Atomic number $Sc = 21,\, Fe = 26, \,Ti = 22, \,Mn = 25)$

Answer

Correct option: A.
$S{c^{3 + }}$
a
(a)$_{21}Sc \to 1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}4{s^2}3{d^1}$

$S{c^{ + 3}} \to 1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}$

Due to presence of paired electron it will be colourless.

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