JEE Main 2024 — 1 February, Shift 2 — Question 61

3rd Ionisation energy : [NCERT Data]

$\mathrm{V}: 2833 \mathrm{KJ} / \mathrm{mol}$

$\mathrm{Cr}: 2990 \mathrm{KJ} / \mathrm{mol}$

$\mathrm{Mn}: 3260 \mathrm{KJ} / \mathrm{mol}$

$\mathrm{Fe}: 2962 \mathrm{KJ} / \mathrm{mol}$

alternative

$\mathrm{Mn}: 3 \mathrm{~d}^{5} 4 \mathrm{~s}^{2}$ Fe: $3 \mathrm{~d}^{6} 4 \mathrm{~s}^{2}$ $\mathrm{Cr}: 3 \mathrm{~d}^{5} 4 \mathrm{~s}^{1}$

$\mathrm{V}: 3 \mathrm{~d}^{3} 4 \mathrm{~s}^{2}$

So Mn has highest 3rd IE among all the given elements due to $\mathrm{d}^{5}$ configuration.