⭕️Since the core orbitals are full occupied , we will consider for the valence shell (2nd shell).
⭕️ in the antibonding shell, highest energy, the last two electrons fill singly ,because both the [π*(2Px)]1 [π*(2Py)]1 orbitals have nearly equal energy.
⭕️So, according to Hund's rule the last two electrons are filled singly.
⭕️Due to this the ,O2 molecule contains unpaired electrons, which characterizes its paramagnetic character...................
Answers & Comments
1s2 2s2 2p4 and the O2 molecule has total 16 electrons.
⭕️according to MO theory, all the 16 electrons will be counted during formation of MO-diagram.
✔️✔️so electronic configuration will be :-
[σ(1s)]2 [σ*(1s)]2 [σ(2s)]2 [σ*(2s)]2 [σ(2Pz)]2 [π(2Px)]2 [π(2Py)]2 [π*(2Px)]1 [π*(2Py)]1 ....
⭕️Since the core orbitals are full occupied , we will consider for the valence shell (2nd shell).
⭕️ in the antibonding shell, highest energy, the last two electrons fill singly ,because both the [π*(2Px)]1 [π*(2Py)]1 orbitals have nearly equal energy.
⭕️So, according to Hund's rule the last two electrons are filled singly.
⭕️Due to this the ,O2 molecule contains unpaired electrons, which characterizes its paramagnetic character...................