Why does argon not form diatomic molecules like oxygen and nitrogen ?

Explanation

All the orbitals (which are occupied by the electrons) are completely filled in argon and hence it has no tendency to share electrons with other atom of Ar to form diatomic molecules. O and N, on the other hand, have unpaired electrons and hence share these electros with other O ans N atom respectively forming `O_(2) and N_(2)` molecules.