Compounds are substances which are composed of two or more elements. Water is one of the simple compound composing of two elements called hydrogen and oxygen. The symbol of water is H₂O.

Below is a table consisting of a list of common elements and their symbols. These elements can readily react with one another to form compounds. All of the elements known are listed on Periodic table.

Pure water, regardless of its source, consists of 11% hydrogen and 89% Oxygen by mass.