Among $\mathrm{Sc^{3+}}$, $\mathrm{Ti^{4+}}$, $\mathrm{V^{2+}}$ and $\…

Question

Among $\mathrm{Sc^{3+}}$, $\mathrm{Ti^{4+}}$, $\mathrm{V^{2+}}$ and $\mathrm{Zn^{2+}}$, which is **coloured** in aqueous solution?

Accepted Answer

C. $\mathrm{V^{2+}}$

Colour in transition-metal aquo ions comes from $d$-$d$ transitions, which require partially-filled $d$-orbitals.
$\mathrm{Sc^{3+}}$ ($d^0$), $\mathrm{Ti^{4+}}$ ($d^0$) and $\mathrm{Zn^{2+}}$ ($d^{10}$) all have either empty or completely filled d-shells, so they are colourless.
$\mathrm{V^{2+}}$ is $d^3$, giving a violet colour in solution.

Answer

$\mathrm{Sc^{3+}}$

Answer

$\mathrm{Ti^{4+}}$

Answer

$\mathrm{Zn^{2+}}$

Among $\mathrm{Sc^{3+}}$, $\mathrm{Ti^{4+}}$, $\mathrm{V^{2+}}$ and $\mathrm{Zn^{2+}}$, which is coloured in aqueous solution?

Keep practising The d- and f-Block Elements & Coordination Compounds