Predict which of he ions `Cu^(+), Sc^(3+), Mn^(2+), Fe^(2+)` are coloured in aqueous solution ? Give reasons.

Explanation

Only those ions will be coloured which have incomplete d-orbitals. Ions which has complete or vacant d-orbitals are colourless.

As `Sc^(3+) and Cu^(+)` have `3d^(0) and 3d^(10)` configuration in their valence shell so their aqueous solutions are colourless. All others, i.e., `Ti^(3+), V^(3+), Mn^(2+) Fe^(+2) and Co^(2+)` are coloured in aqueous medium.