Chemical Elements

A chemical element which is usually called simply an element, is a substance that cannot be decomposed or transformed into other chemical substances by ordinary chemical processes. All matter consists of these elements and as of 2006, 117 unique elements have been discovered or artificially created. The smallest particle of such an element is an atom, which consists of electrons centered about a nucleus of protons and neutrons.

Earlier an element or pure element was defined as a substance which �cannot be further broken down into another compound with different chemical properties"�which should be taken to mean it consists of atoms of one element. The lightest elements are hydrogen and helium. Lists of the elements by name, by symbol, by atomic number, by density, by melting point, and by boiling point as well as Ionization energies of the elements are available.