[student8607]

I know that in determining whether a molecule is polar, nonpolar or ionic that you have to look at electronegativities

0=nonpolar
0<x<2.0=polar
x>2.0=ionic

but how would you answer something that asked about the "largest degree of polarity" and explain why?
a. CF4
b. CO2
c. CN-

[enahs]

Draw the structures.

Any of them symmetrical? If so, what does that mean about polarity?
What effect on polarity would a charge do?