The chemical bonds of a water molecule are formed by interactions of electrons. A hydrogen atom has one electron in its orbital. Oxygen has six electrons in its outer orbitals.As a rule, atoms like to have their outer orbitals full. Since oxygen lacks two electrons, and hydrogen lacks one, two of the electrons from the oxygen form covalent bonds with each of two hydrogens' electrons. This means there are two pairs of electrons left on the oxygen atom once the water molecule is formed.These are extended above and below the H-O-H plane and away from the hydrogens. This results in a tetrahedrally-shaped molecule. The angles between the O-H bonds and the lone pairs of electrons are all 109.5o and their distance from one another measures .957 angstroms. This bent shape of the water molecule means that the electrons aren't spread out equally, and so the molecule is said to be polar. Polar molecules can undergo hydrogen bonding. The hydrogen bond is an attraction between a positive pole of one molecule and a negative pole of another. This association greatly impacts how water functions in foods.

The many properties of water are due to the uniqueness of hydrogen bonding. Although fairly week in comparison to covalent bonding, the ability of one water molecule to form links with four other polar molecules is influencial.

The relative strengths of various bonds are shown below.