Chemical Bonding and Molecular Structure

The pair of molecules that have the same bond order are O2 and C2.
Bond order shows how many chemical bonds are between two atoms.
To find bond order, use this formula:
‌ Bond Order ‌=‌

‌ Number of bonding electrons ‌‌-Number of antibonding electrons ‌

2

For O2 :
Number of bonding electrons =10,
Number of antibonding electrons =6
Bond Order =‌

10−6

2

=2
For C2 :
Number of bonding electrons =8,
Number of antibonding electrons = 4
Bond Order =‌

8−4

2

=2
So, both O2 and C2 have a bond order of 2 .