Determine the bond order in a molecule or ion with 10 valence electrons.

Bond order = 1

Explanation:

The 10 valence electrons can be added across bonding and antibonding molecular orbitals (MO) in a manner shown below:

- two 1s orbitals combine to form σ1s and σ*1s with 2 electrons in each MO

- the 3 p-orbitals combine to form σ2pz, σ*2pz with 2 electrons in each MO. In addition a degenerate π2py, π2px and π*2py, π*2px with a total of 4 electrons in each set of degenerate orbitals

Based on the energy level ordering the 10 electrons can be distributed across the bonding MO's as follows

(σ1s)²<(σ*1s)²<(σ2s)²<(σ*2s)²<(π2py)¹ = (π2px)¹

Bond order = 1/2(Bonding electrons - non-bonding electrons) = 6-4/2 = 1

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be