Question

oxygen has lower first ionization enthalpy than nitrogen and fluorine

Answer 1

So oxygen would readily loose an electron to attain a stable configuration that is half filled configuration. So first Ionization energy of nitrogen is more than first ionization energy of Oxygen. the p orbital of nitrogen havethree electrons (p can accommodate 6, but here partly filled)



.To become stable, both fluorine and oxygen must achieve a full octet, or set of 8 electrons in their outer shells. Therefore, it is more difficult to remove an electron from fluorine than from oxygen, giving it the higher ionization energy (highest one on the periodic table).


hope it helps