Question

The aqueous solution containing which one of the following ions will be colourless?

• A. $S{c}^{3+}$
• B. $F{e}^{2+}$
• C. $T{i}^{3+}$
• D. $M{n}^{2+}$

Answer 1

The correct option is A $S{c}^{3+}$

The colour of the transition metals is mainly due to the electronic transitions in the d orbitals.
$S{c}^{+3}⟶1s^{2}2s^{2}2p^{6}3s^{2}3p^6$
Since it does not have any electron in $3d$ subshell, thus it is colourless.