JEE Mains · Chemistry · STD 11 - 2. structure of atom
The ionization energy of sodium in \(\mathrm{kJ} \mathrm{mol}^{-1}\). If electromagnetic radiation of wavelength \(242 \mathrm{~nm}\) is just sufficient to ionize sodium atom is _______.
- A \(494\)
- B \(490\)
- C \(499\)
- D \(445\)
Answer & Solution
Correct Answer
(A) \(494\)
Step-by-step Solution
Detailed explanation
\(\mathrm{E}=\frac{1240}{\lambda(\mathrm{nm})} \mathrm{eV}\) \(=\frac{1240}{242} \mathrm{eV}\) \(=5.12 \mathrm{eV}\) \(=5.12 \times 1.6 \times 10^{-19}\) \(=8.198 \times 10^{-19} \mathrm{~J} / \text { atom }\) \(=494 \mathrm{~kJ} / \mathrm{mol}\)
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