# Homework Help: Which are polar or nonpolar?

1. Mar 18, 2007

### linuxux

1. The problem statement, all variables and given/known data
The question asks which are polar or non-polar: $$ClO_{4}^{-},H_{2}S,SF_{6},PCl_{3}$$ ?

All molecules are tetrahedral and polar except for $$SF_{6}$$ which is octahedral and nonpolar.

Last edited: Mar 18, 2007
2. Mar 18, 2007

### jakcn001

It has something to do with the electron configuration. Like H-S-H, it is not linear. And the center of H is not the same as S. So you can analysize the electron configuration.Therefore you can determine whether it is polar or not.

3. Mar 18, 2007

### Hootenanny

Staff Emeritus
linuxux, you may wish to consider the relative electronegativity values of each atom that makes up the molecule.

As an aside, not all molecular gasses are polar; take hydrogen, chlorine, methane for example. Polarity depends not only on the electronegativity of each atom, but also the actual shape of the molecules themselves.

4. Mar 18, 2007

### linuxux

i already did all the lewis dot diagrams, they all fit into the electrostatic repulsion geometry, the only one that didn't have an all symmetric geometry was $$PCl_{3}$$, unless i did something wrong, i haven't considered electro negativity yet however.

Last edited: Mar 18, 2007
5. Mar 18, 2007

### linuxux

okay, is any of that right?...