Which of the following is paramagnetic? — Atomic Structure Chemistry Question

💡 Solution & Explanation

Paramagnetic species have unpaired electrons. (a) Zn$^{2+}$ is $3d^{10}$ (all paired). (b) Ni$^{2+}$ is $3d^8$ (2 unpaired). (c) Sc$^{3+}$ is $3d^0$ (all paired). (d) O$^{2-}$ is $2p^6$ (all paired). Only Ni$^{2+}$ is paramagnetic. Therefore, correct answer is B.