Which one of the following complexes will most likely absorb visible light? (At nos. Sc =21, Ti =22, ~V =23, Zn =30 )

Step-by-step solution

The absorption of visible light and hence coloured nature of the transition metal cation is due to the promotion of one or more unpaired - d - electron from a lower to higher level within same d -subshell. Hence higher will be the number of unpaired electron higher will be the absorpion in visible light. The electronic configuration of the given elements is Sc ³⁺(18)=1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 3 d^0 4 s^0- no unpaired e ⁻ . Ti ⁴⁺(18)=1 s^2 2 ~s ^2 2 p^6 3 s^2 3 p^6 3 d^0 4 s^0- no unpaired e ⁻ . V ³⁺(20)=1 s^2 2