What Is a Polar Substance?

When two atoms form a covalent bond, they each share an electron. Different atoms have different abilities to attract electrons quantified by their electronegativity values. When one atom in a covalent bond has a much higher electronegativity than the other, the electron is found closer to that atom than the weaker one. This creates a dipole effect with a slight negative charge at the atom the electron favors and a slight positive charge at the other.