What makes a compound polar or nonpolar?

Question

We are discussing the lewis structure of compounds however, i cannot find any subject on determining when a compound is polar or nonpolar? Does it have to do with its electronegitivity?

Answer 1

It is indeed the electronegativity. Take the EN difference between the 2 atoms.

If it is greater than 1.7 it will be ionic
Between 0,5 and 1.7 polar covalent
Below 0.5 it will be non polar covalent.

The transition is not sharp, it is more like a gradual shift.