Ionic Bonds: Electrons are transferred b/c one atom "steals" electrons from another. The attraction between the resulting cation/anion is known as an ionic bond.
Polar Covalent Bonds: Electrons are shared <em>unequally</em>. This is in the case that the molecule is not symmetric or if the central atom has a lone (electron) pair.
Nonpolar Covalent Bonds: Electrons are shared <em>equally</em>. This is in the case that the molecule is symmetric and the central atom has no lone pairs.
