Answer is : (d) O2
The species formed after removal of an electron from the given diatomic molecules are as follows
The stability of diatomic molecule can be determined by calculating its bond order. More is the bond order, more is the stability of a molecule.
B.O = 1/2 (Nb - Na)
∴ The bond orders of diatomic molecules with their ionic species are given below.
As the bond order increases from 2 to 2.5 when an e− is removed from O2 molecule \((O^+_2),\) so it become stabilised.