Question

The ionization energy of nitrogen is more than that of oxygen because :

• A. of the extra stability of half-filled p orbitals in nitrogen
• B. of the smaller size of nitrogen
• C. the former contains less number of electrons
• D. the former is less electronegative

Answer 1

Answer: (A)

Ionization energy is the minimum energy required to remove the most loosely held electron from one mole of gaseous atoms to produce one mole of gaseous ions each with a charge of $+1$.

An atom is highly stable when its valence orbital is completely filled or half-filled and in nitrogen, the valence p orbital is exactly half filled. So, p orbital in nitrogen is more stable than in oxygen, which has one electron more than the half-filled configuration. So, the ionization energy of nitrogen is more than that of oxygen.