Question

How to determine that compound is polar and non polar?

Answer 1

Electronegativity differences, net dipole moments, Shape of molecule , Whether the molecule is symmetrical (non polar) or not.

Answer 2

You have a polar molecule when you have a covalent bond and the atoms bonded together have a big difference in electronegativity. First remember that a covalent bond forms between 2 nonmetals where they share electrons. With a polar covalent bond, it means that whats happening here is that they dont share the electrons equally. Instead, the electrons spend most of their time around the more electronegative element. So now in the molecule you have a partial positive charge and a partial negative charge. The partial negative charge will be around that super electronegative element.

For example, HF. The electronegativity of H=2.1 and F=4.1

Sothere is a huge difference in electronegativity which is 2.
This means you have a polar molecule because they are both nonmetals, and you have a partial positive charge on the H end and a partial negative charge on the F end.

Now if you have an atom like N bonded to itself, there is no difference in electronegativity because the electronegativity of N=3. So 3-3= 0. These type of molecules that are formed diatomically are always nonpolar, since there is no difference in electronegativity.

N2 nonpolar

CS2 C=2.5 and S=2.4 so difference is .1 which is very small difference so we would not call that polar. We would just say primarily covalent.

Remember nonpolar just means when the difference is zero.

Ok CH3F, here you have F bonded to C so 4.1- 2.5 = 1.6.
Here wed say polar covalent bond
also watch this
www.youtube.com/watch?v=PcJRH2ojkZA