[THISMOMENTISFATE]

im having a hard time distinguishing between polar and nonpolar. can anyone explain simply how to know? ive looked around the net but i just get more confused. lol i have a test soon, please help?

[Jorriss]

Do you know what electronegativity is?

[THISMOMENTISFATE]

Do you know what electronegativity is?

i know that the closer an element is to F (up and to the right) the more electronegative it is.

[Jorriss]

That's knowing a pattern in predicting whats more electronegative, but do you know what it means for an atom to be electronegative?

[THISMOMENTISFATE]

when it has negative electric charge and it will attract elections so it can form a chemical bond.

[Jorriss]

when it has negative electric charge and it will attract elections so it can form a chemical bond.

Almost, careful with the second part, there are some consequences that help form chemical bonds but not so explicitly.

The idea is simpler, an electronegative atom pulls electrons from a less electronegative atom.

Suppose we have the simple diatomic, H-F. Fluorine is a lot more electronegative than hydrogen, so fluorine will pull the electrons in the molecule toward itself. Meaning there is a little bit of negative charge on fluorine (not a full negative charge, not quite) and a bit of positive charge on hydrogen. This uneven distribution of charge is a polar bond.

Look at an even simpler diatomic, H-H. In this case, hydrogen and another hydrogen have identical electronegativities so each hydrogen has an equal share of the electrons and there is no dipole (dipole and polar are often interchangeable words).

So tell me, are the following molecules polar or non polar and try and highlight your thought process.

HCl, H2S, CCl4

[opti384]

One concept related to the polarity of the molecules is the dipole moment which is a vector quantity. Keeping this in mind will help you discern some molecules that seems to be polar but actually are not.