Elements

Elements, CHEMICAL, the simplest known constituents of all compound substances. Chemists regard as elementary substances or elements only those substances which have not been proved to be compound. It is not inconceivable that some of the substances at present designated elements (for list of known elements, see ATOMIC THEORY) may hereafter be proved to consist of more than one simple kind of matter, but in the meantime they are correctly called elements, as that term is applied above. The elements are somewhat arbitrarily divided into non-metals and metals, the latter forming by far the larger class. There is no sharp line of demarcation between the two classes, several elements occupying positions on the border line. The elements long classed as non-metals were: Hydrogen (in chemical relations behaving like a metal), chlorine, bromine, iodine, fluorine, oxygen, sulphur, selenium, boron, nitrogen, phosphorus, carbon, silicon. But the list was increased by the discovery of helium and argon (1895), and krypton, neon, and metargon (1898). Many hold that all the elements are composed of one fundamental elementary substance (see also CHEMISTRY, and METALS). The time-honoured 'Four Elements' of the Greeks—air, fire, water, earth—are discussed at EMPEDOCLES. The 'Shoo-king,' a Chinese work older than Solomon, has five elements—water, fire, wood, metal, earth. The Indian Institutes of Manu have also five—subtle ether, air, fire, water, and earth. For Helium and Argon, see ARGON.