Covalent bonding is a type of chemical bond where two atoms share electrons to achieve stability. This sharing allows each atom to fill its outer electron shell, which is crucial for forming molecules. For example, in a water molecule, two hydrogen atoms share electrons with one oxygen atom, creating a stable structure. This bonding typically occurs between nonmetals, such as carbon, oxygen, and nitrogen. The strength of a covalent bond depends on how many pairs of electrons are shared; single, double, and triple bonds represent one, two, and three pairs of shared electrons, respectively. This sharing leads to the formation of various compounds essential for life.