Among the following, the molecule formed by s-p overlapping is           

HF molecule is formed by end on end overlapping of s orbital of H atom and p orbital of F atom  whereas remaining  all ${\text{N}}_2$ ,${\text{F}}_2$ ,$\text{C}{l}_2$  molecules are formed by

 p-p overlapping of p orbitals and forms one $\sigma$   bond in ${\text{F}}_2$ ,$\text{C}{l}_2$ molecules and one $\sigma$ and two $\text{π}$ bonds are formed in ${\text{N}}_2$ molecule.