Question

The ionization energy of $H{e}^{+}$ ion in ground state may be:

• A. $13.6eV$
• B. $54.4eV$
• C. $108.8eV$
• D. $27.0eV$

Answer 1

The correct option is B $54.4eV$

Solution:

The He+ ion is just like a hydrogen atom with two units of charge in the nucleus. Since the hydrogenic energy levels depend upon the square of the nuclear charge, the energy of the remaining helium electron should be just $4X(-13.6ev)=-54.4ev.$