Chemical elements are the basic chemical substances; that is, they cannot be decomposed by chemical change or made by chemical union. These elements follow a periodic pattern related to the atomic mass of each that allows them to be arranged into a convenient table. This article includes a series of tables: the first gives the names and symbols of the elements in alphabetical order and the second lists the elements in order by atomic number and give the atomic weight for each. The periodic table of the elements also is included in the article.