Which is an acceptable lewis structure for a diatomic nitrogen molecule?

            Acceptable Lewis structure of Diatomic Nitrogen Molecule is as follow,

                                                      :N≡N:

Explanation:
                     The given lewis structure is acceptable because each nitrogen atom has a complete octet and and the formal charge of each nitrogen atom is zero. So those lewis structures which has zero or least formal charges are said to be more stable and acceptable. The formal charge is calculated is,

Formal Charge  =  # of Valence e⁻s - [# of non-bonded e⁻ + 1/2 # of bonded                                           e⁻]

For N,

Formal Charge  =  5 - [ 2 + 6/2]

Formal Charge  =  5 - [ 2 + 3 ]

Formal Charge  =  5 - 5

Formal Charge  =  0

Same result will come for the second N atom.