Question

Ionization energy of $H{e}^{+}$ is 54.4 eV. The ionization energy of $L{i}^{2+}$ is:

• A. 54.4 eV
• B. 122.4 eV
• C. 27.2 eV
• D. 40.8 eV

Answer 1

The correct option is B 122.4 eV

Ionization energy of hydrogen like species is given by the equation
= $13.6\times Z^{2}eV$
For, $H{e}^{+}=13.6\times 2^{2}eV=13.6\times 4eV=54.4eV$
$\therefore ForL{i}^{2+}=13.6\times 3^{2}eV=13.6\times 9eV=122.4eV$