JEE Main 2026 — 21 January, Evening Shift — Question 67

$\mathrm{V}^{3+}=(\mathrm{Ar})_{18} 3 \mathrm{~d}^{2}$ $\mathrm{Ti}^{2+}=(\mathrm{Ar})_{18} 3 \mathrm{~d}^{2}$ $\mathrm{Ni}^{2+}=(\mathrm{Ar})_{18} 3 \mathrm{~d}^{8}$ $\mathrm{Fe}^{2+}=(\mathrm{Ar})_{18} 3 \mathrm{~d}^{6}$ $\mathrm{Co}^{2+}=(\mathrm{Ar})_{18} 3 \mathrm{~d}^{7}$ Only for $\mathrm{Fe}^{2+}$ and $\mathrm{Co}^{2+} \mu$ is more than 3.0 B.M. ∴ Number of unpaired electrons $=4+3=7$