Chemistry of Water

A water molecule (H2O) consists of one oxygen atom covalently bonded to two hydrogen atoms. Oxygen is far more electronegative than hydrogen, so it pulls the shared bonding electrons closer to itself; this makes the oxygen end of the molecule slightly negative and the two hydrogen ends slightly positive, turning water into a small polar molecule. Because of this polarity, the slightly positive hydrogen of one water molecule is attracted to the slightly negative oxygen of a neighbouring water molecule, forming a weak but abundant network of hydrogen bonds. This attraction between identical water molecules is called cohesion, and it is strong enough to pull water molecules into an ordered lattice arrangement, for example as ice forms. Because it is small and polar, water can als …