In chemistry, a polar bond is a type of covalent bond between two atoms or more in which electrons are shared unequally. The two atoms have a different electronegativity. So the bonding electrons are attracted to one nucleus a little more than to the other. Because of this, one end of the molecule has a slight, relative negative charge and the other a slight, relative positive charge. An example of atoms bonded by a polar bond is the water molecule (H2O), which is made up of two hydrogen atoms and one oxygen atom. The oxygen atom is more electronegative than the hydrogen atom in each bond.