Question

the ionisation enthalpy of nitrogen is more than oxygen why/////////////////

Answer 1

since nitrogen has small atomic size than oxygen that is why ionisation enthalpy of nitrogen is more than that of oxygen

Answer 2

Answer:

(1) The electronic configuration of nitrogen (N, Z = 7) is 1s², 2s², 2p³ and that of oxygen (O, Z=8) is 1s², 2s² 2p^4.

(2) Nitrogen atom acquires extra stability due to half- filled 2p-orbitals while oxygen can acquire half-filled orbital and extra stability by losing one electron. Thus, oxygen can easily lose one electron.

(3) Nitrogen requires more energy to remove an electron due to extra stability. Therefore, first ionisation enthalpy of oxygen is less than that of nitrogen.