Which of the following ion is diamagnetic? — Atomic Structure Chemistry Question

💡 Solution & Explanation

Diamagnetic ions have zero unpaired electrons. (a) Sc$^{3+}$ is $[Ar] 3d^0$, so 0 unpaired. (b) Ti$^{2+}$ is $3d^2$ (2 unpaired). (c) V$^{3+}$ is $3d^2$ (2 unpaired). (d) Fe$^{2+}$ is $3d^6$ (4 unpaired). Sc$^{3+}$ is diamagnetic. Therefore, correct answer is A.