Which of the following ion is expected to be coloured? — Atomic Structure Chemistry Question

💡 Solution & Explanation

Color in transition metal ions arises from d-d transitions, which require partially filled d-orbitals. (a) Zn$^{2+}$ ($3d^{10}$) is fully filled. (b) Ca$^{2+}$ has no d electrons. (c) Sn$^{2+}$ is a p-block element with a $4d^{10} 5s^2$ core. (d) V$^{2+}$ is $3d^3$, which is partially filled. Therefore, correct answer is D.