Here on this example question it says determine if carbon tetrachloride which is CCl4 is polar or nonpolar. So here remember when we draw Lewis down structures we place the least electronegative element in the center. In this case it would be carbon. Carbon here is in Group 4A so it has four valence electrons. So we're going to draw our four valence electrons.
Our chlorines are in Group 7A, so they each have 7 valence electrons. And remember carbon wants to make four bonds or must make four bonds. So each chlorine will form a single bond with our carbon. Now if we take a look at the structure, we're going to say that our central element has the same surrounding elements and it has no lone pairs on it.
It would be defined as a perfect shape one and as a result of being a perfect shape it would be nonpolar. So here we're going to say that carbon tetrachloride is a nonpolar molecule.
