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 is : 494

\(E = \frac {1240}{\lambda (nm)}eV\)

\(= \frac {1240}{242}eV\)

= 5.12 eV

\(= 5.12 \times 1.6 \times 10 ^{-19}\)

\(= 8.198 \times 10^{-19} J/atom\)

= 494 kJ/mol