Question

the first ionisation energy of Nis greater than O.why​

Answer 1

the first ionisation energy of flourine is greater than oxygen because in oxygen ionisation takes place in the way that firstly it forms o– then it forms o²-so it req more energy to break two o atoms and we know flourine is more ectronegative than oxygen because from going left to right electron gain enthalpy increase s hence flourine can gain electrons easily so it has higher ∆igh. i.emore enthalpy

Answer 2

Because oxygen is electronegative element and has more  atomic radius than Nis.