Question

Why are the ionisation energies of group 15 elements much higher than those of the corresponding elements of group 14?

Answer 1

1. Group 15 elements have a higher nuclear charge than group 14 elements in the same period.
2. Their atomic size is smaller because electrons are held more tightly by the nucleus.
3. Group 15 atoms have a stable half-filled (np³) subshell, which adds extra stability to their electronic configuration.
4. This stability means they less readily lose their valence electrons.
5. Consequently, it requires more energy (higher ionisation energy) to remove an electron from group 15 elements compared to group 14.

These points explain why ionisation energies of group 15 elements are significantly higher than those of group 14 elements.