[عاطف خليفة]

Here is the full molecular orbital diagram for N2.



Now we add the 10 electrons, 5 from each nitrogen atom. Note that the bottom sigma symmetry orbital is strongly bonding, the top one is strongly antibonding, and the 2 in the middle are only weakly bonding and antibonding, respectively. The 2 and 3 orbitals correspond to the non-bonding electron pairs in the Lewis structure. There is one sigma bond and 2 pi bonds when the 10 electrons are added to the lowest energy molecular orbitals.