Polar or nonpolar molecules?

Question

1. NO2-
2.N3-
3.SO3
4.ClO3-
5.CCl4

please help, I am pretty sure that ClO3 is polar and CCl4 is nonpolar, but I'm not sure really how to figure it out, please help!!

Answer 1

1. bent, lone pair, polar
2. single monatomic ion - non-polar
3. trigonal planar and perfectly symmetrical - non-polar
4. the - is shared between all the O atoms. Trigonal planar and therefore symmetrical and non-polar.
5. totally symmetrical and non-polar

Answer 2

1. bent, lone pair, polar
2. single monatomic ion - non-polar
3. trigonal planar and perfectly symmetrical - non-polar
4. Polar because it has a lone pair on the Cl
5. totally symmetrical and non-polar

Answer 3

Please note that any given with charges is already ionic, which means it is more than polar --- it is ionic. So, #s 1,2 and 3 are "polar" or technically ionic. #3 is NON-POLAR because even though the S-O dipoles are polar they cancel each other .#5 CCl4 is NON-POLAR also because the dipoles of each of the individual polar C-Cl cancel each other.