what are polar and non polar molecules?

 

Polar molecules are formed by elements whose atoms have different electronegativities. The electrons forming the bonds will have a tendency to be attracted closer to the more electronegative element. In such instances covalent molecules develop some ionic character and are called polar molecules.

As a result of polarity, a small negative charge ( δ -) appears on the more electronegative atom and a small electropositive charge ( δ +) appears on the less electronegative atom. For example: In HCl molecule, Cl atom is more electronegative. As a result it acquires a ( δ -) charge and H acquires a ( δ -) charge. Thus, it is a polar molecule.

Non- polar moleculesare formed between two different types of atoms having more or less identical electronegativities. Example: methane (CH ₄ ).