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

The correct option is A of the extra stability of half-filled p orbitals in nitrogen

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.