Question

Second ionization enthalpy of nitrogen is lower than oxygen give reason

Answer 1

Answer:

This is due to an electron being added to an already half full orbital in oxygen, which results in electron electron repulsion, which will lower the ionisation energy. Nitrogen also has the added stability of a half filled shell of electrons in the 2p shell.

Answer 2

Oxygen reaches a half filled 2p orbital and the removal of an electron from that 2p orbital requires lots of energy, hence the second ionization enthalpy pf Oxygen is high
Nitrogen has very high first ionization enthalpy cuz of half filled 2p orbital
Once that electron’s removed from the 2p orbital, removing another electron comparatively requires lesser energy. Hence the second ionization enthalpy of Nitrogen is lower