CO₂ has 4 + 2(6) = 16 valence electrons
CO₂ have linear molecular structures with a 180° bond angle. CO₂ is nonpolar because the individual bond dipoles cancel each other out
XeCl₂ has 8 + 2(7) = 22 valence electrons.
There are five pairs of electrons about the central Xe atom. The structure will be based on a trigonal bipyramid geometry. The most stable arrangement of the atoms in XeCl₂ is a linear molecular structure with a 180° bond angle. It is nonpolar because the Xe−Cl bond dipoles and lone pairs around Xe are arranged in such a manner that they cancel each other out.
(b)
SCl₆ is nonpolar because it has 6 bonding pairs and no lone pairs, giving it an octahedral shape. When you draw the vectors, you can see that the resultant is 0, making it nonpolar.
SCl₄ on the other hand is polar because it has 4 bonding pairs and one lone pair, giving it a trigonal pyramidal shape.
SCl₂ is also polar due to reasons similar to those in the case of SCl₄.