Question

Why nitrogen has positive electron gain enthalpy whereas oxygen has negative?

Answer 1

◆Due to this extra stable electronic configuration, it is difficult to remove an electron from the valence shell ofnitrogen (or any other Group 15 element) and thus more energy is required. Thus ionization enthalpy ofnitrogen is higher than oxygen

Answer 2

Nitrogen has positive electron gain enthalpy whereas oxygen has negative. However, oxygen has lower ionisationenthalpy than nitrogen. ... Nitrogen hasstable configuration because /(-orbital is half-filled. Therefore, addition of extraelectron to any of the /(-orbital requires energy..