Electromagnetic radiations of wavelength 240 nm are just sufficient to ionize sodium atom. The ioniz — Atomic Structure Chemistry Question

💡 Solution & Explanation

Energy per photon $E = \frac{1240 \text{ eV}\cdot\text{nm}}{240 \text{ nm}} \approx 5.167$ eV. To convert to kJ/mol, multiply by $96.485$ (since $1 \text{ eV} = 96.485 \text{ kJ/mol}$). $5.167 \times 96.485 \approx 498.5$ kJ/mol. Therefore, correct answer is B.