Ionization enthalpy of nitrogen is more than that of oxygen. Explain why?

Explanation

It can be explained on the basis of symmetrical arrangement of electrons in 2p orbitals of nitrogen.
`N(Z=7)=1s^(2)2s^(2)2p^(1),2p_(x)^(1)2p_(y)^(1)2p_(z)^(1), O(Z=8)=1s^(2)2s^(2)2p_(x)^(2)2p_(y)^(1)2p_(z)^(1)`
Nitrogen has stable half filled electronic configuration. On the other hand, oxygen contains unsymmetrical distribution of electrons. So, more energy is required to remove the electrons from the outermost shell of N than O. Therefore, ionization enthalpy of nitrogen is more than the oxygen.