JEE Main 2014 · 12 Apr · Shift 1, Chemistry question 50

Colour needs partly filled d orbitals.

• $\ce{Sc^3+}$: $d^0$.
• $\ce{Ti^4+}$: $d^0$.
• $\ce{Zn^2+}$: $d^{10}$.
• $\ce{V^3+}$: $d^2$, so d-d transitions absorb visible light.