Write the Lewis structure for each molecule.
In PH3 the central atom is P, surrounded by three H atoms.
15P [Ne] 3s2 3p3 1H 1s1
Total number of valence electrons = 5 + 1(3) =8
Lewis structure of PH3
In SCl2, the central atom is S, surrounded by Cl atom.
16S [Ne] 3s2 3p4 17Cl [Ne] 3s2 3p5
Total number of valence electrons = 6 + 7 (2)= 20
Lewis structure of SCl2