Predict which atom in each of the following pairs has the greater first ionization enthalpy and explain your answer (a) B and C ( b) N and O ( c) F and Ne

Answer

(a) C has greater first ionisation enthalpy because as we move from left to right in a period the ionisation enthalpy increases
(b)
Out of N and O, nitrogen has higher first ionisation enthalpy becuase in case of N the electron is to be removed from a half filled sub-shell as its electronic configuration is `1s^2 2s^2 2p^3` whereas in case of oxygen the electronic configuration is `1s^2 2s^2 2p^4` so it is easier to remove an electron in comparison to N
(C ) Ne has higher ionisation enthalpy as it is a noble gas and it has electronic configuration `1s^2 2s^2 2p^6` , the outermost shell is fully filled so it gets tougher to remove an electron in comparison to F.

Explanation

(a) C has higher `Delta_(i)H_1)` than B because of higher nuclear a charge
(b) N has higher `Delta_(i) H_(1)` than O beacause in case N, the electron has to be lost from a more stable exactly half- filled electronic configuration
( c) Ne has higher `Delta_(i) H_(1)` than F bacause of stable inert gas configuration