Q.No.21 :Why There is difference in the energy levels of O2 and N2 2px,2Py and 2Pz

Reasoning Question Series
Q.No.21 :Why There is difference in the energy levels of O2 and N2 2px,2Py and 2Pz
Ans:
1. its due to the energy difference between Nitrogen and Oxygen
Oxygen = 1595 kj/mol
Nitrogen = 1195 KJ/mol
its energy difference b/w 2s and 2p orbitals which can determine with the help of spectroscopy
2. sigma 2s and sigma star 2s have not pure s character (Stable and Lower energy)
and sigma 2px and sigma star 2px have not pure p character
less stable and Higher energy level)
3. if energy differtence is larger then mixing will not occur
4. The mixing does not occur with O2 and F2 due to large energy difference between 2s and 2px orbitals.
5.Thus energy of sigma 2px is raised so much that it goes higher than pi 2py=pi 2pz bonding orbitals
Rgards
Malik Xufyan