Since we know that, more is the bond order of any species, shorter will be its bond length and hence, stronger will be the bond.
N2
>
O2
>
F2
Bondorder
3
2
1
As bond length is reverse of bond order, therefore, the correct order of bond length will be: F2>O2>N2 The order of dissociation energy is as follows: N2>O2>F2