Chemistry - CHEMICAL BONDING Question with Solution | TestHub

For O₂:

The MO configuration is ${\sigma }_{2s}^2{\sigma }_{2s}^{\ast 2}{\sigma }_{2p_z}^2{\pi }_{2p_x}^2{\pi }_{2p_y}^2{\pi }_{2p_x}^{\ast 1}{\pi }_{2p_y}^{\ast 1}$.

2s orbitals have an energy of $-32.38eV$, while 2p orbitals have $-15.85eV$.

Bonding electrons above $-32.38eV$: All 2p-derived bonding electrons = $2+2+2=6$, so $X=6$.

Antibonding electrons below $-32.38eV$: ${\sigma }_{2s}^{\ast 2}$ lies below this reference, so $Y=2$.

Therefore, $X+Y=6+2=8$.