Polar molecules occur when two atoms do not share electrons equally in a covalent bond. While polar molecules have two parts with opposite charges (i.e., positive and negative), nonpolar molecules have no dipole, meaning that there is molecular symmetry, which results in no opposing charges.
Answer: The greater the electronegativity difference, the more ionic the bond is. Bonds that are partly ionic are called polar covalent bonds. Nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.
