Recall that carbon is the second most common element in our body and is found in all organic molecules. Recall, too, that carbon atoms contain four electrons in their outer electron shell. With this number of electrons, carbon atoms may form up to four single covalent bonds. Covalent bonds involve the sharing of electrons between bonding atoms. What kind of covalent bond is formed when the electrons are NOT shared equally between the bonding atoms, for example, when hydrogen and oxygen atoms bond in a water molecule?