Question

first ionization enthalpy of nitrogen is more than oxygen why

Answer 1

Nitrogen has 3 electrons in its outermost orbital while oxygen has 4 electrons. Out of this 4 electrons 2 are paired. While in nitrogen 3 are unpaired . It is hard to remove electrons from fully filled and half filled orbitals. As oxygen has only one paired that paired electron can be easily removed.

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.