Question

Arrange b c n o in increasing order of their ionisation enthalpy

Answer 1

when we move from left to right atomic size decreases so ionization energy increase

boron< carbon< nitrogen< oxygen

Answer 2

Nitrogen has the highest ionization enthalpy while Boron has the lowest ionization enthalpy:

Ionization enthalpy

• It is the amount of energy/enthalpy that is needed to remove an electron from an atom in its gaseous state.
• Ideally, the ionization enthalpy increases with a decrease in atomic size, thus the expected trend is B < C < N <O
• However, the electronic configuration of nitrogen is 1s²2s²2p³ with a half-filled p orbital which provides N atom with extra stability thus it has a higher ionization enthalpy than O.

Thus, the increasing order of ionization enthalpy will be:  B<C<O<N