Question

The ionization energy of sodium in \(kJ \;mol^{−1}\). If electromagnetic radiation of wavelength 242 nm is just sufficient to ionize sodium atom is ______.

Answer 1

Correct Answer: 494

\[ E = \frac{1240}{\lambda (\text{nm})} \, \text{eV} \]
\[ E = \frac{1240}{242} \, \text{eV} \]
\[ E = 5.12 \, \text{eV} \]
\[ E = 5.12 \times 1.6 \times 10^{-19} \, \text{J/atom} \]
\[ E = 8.198 \times 10^{-19} \, \text{J/atom} \]
\[ E = 494 \, \text{kJ/mol} \]