The magnetic moment of Ni ion () is about 2.82 B.M. The value of is — Atomic Structure Chemistry Question

💡 Solution & Explanation

Magnetic moment $\mu = \sqrt{n(n+2)} = 2.82 \implies n = 2$ unpaired electrons. Nickel ($Z=28$) is $[Ar] 3d^8 4s^2$. To have 2 unpaired electrons, the ion must be $3d^8$, which corresponds to losing the two 4s electrons. This is Ni$^{2+}$, so $x = 2$. Therefore, correct answer is A.