From four elements to chemical elements
Empedocles and Aristotle held that everything was made of earth, water, air and fire, while East Asia had the five phases of wood, fire, earth, metal and water. Alchemists tried and failed to turn metals into gold. In The Sceptical Chymist (1661) Robert Boyle argued that elements must be established by experiment, and in 1789 Antoine Lavoisier defined an element as a substance that chemical analysis cannot split further, listing 33 including oxygen and hydrogen (though, as a sign of the times, light and heat were on the list too). In 1808 John Dalton proposed that each element has its own kind of atom with a characteristic weight.
The periodic table and atomic number
In 1869 Dmitri Mendeleev found that ordering elements by atomic weight made properties repeat periodically; he left gaps for undiscovered elements and predicted their properties. When gallium (1875), scandium (1879) and germanium (1886) turned up as forecast, the table won acceptance; Lothar Meyer in Germany produced a similar table at the same time. In 1911 Ernest Rutherford showed atoms have a tiny nucleus, and in 1913 Henry Moseley used X-ray spectra to show that the true order is the nuclear charge — the atomic number, or number of protons. The repeating pattern is explained by electron arrangements described by quantum mechanics. In 1945 Glenn Seaborg reorganised the bottom of the table with the actinide concept.
Where elements come from
The Big Bang made mostly hydrogen and helium with a little lithium. That heavier elements are forged in stars was systematically set out in the 1957 "B²FH" paper by the Burbidges, Fowler and Hoyle. Stars like the Sun fuse hydrogen into helium by nuclear fusion, and massive stars go on to carbon, oxygen and iron. Many elements heavier than iron are thought to form in supernovae and in collisions of neutron stars, for which a 2017 merger provided evidence — hence the saying that we are made of star stuff. Around 90 elements occur naturally on Earth; the rest are made in accelerators. In 2006 a Russian–US team reported element 118, oganesson, and in 2016 four elements were named, including 113, nihonium, made at Japan's RIKEN. By mass the human body is mostly oxygen, carbon, hydrogen and nitrogen, but trace elements such as iron and iodine are essential.
FAQ
- How is an element different from a compound?
- An element is made of only one kind of atom (e.g. oxygen O₂, iron Fe); a compound is two or more elements chemically bonded (e.g. water H₂O).
- Will element 119 be made?
- Several laboratories are attempting elements 119 and 120, but no success has been confirmed yet; very heavy nuclei are extremely unstable and exist only for fleeting moments.
Sources reviewed: 2026-10-26
References
- Boyle, R. (1661). The Sceptical Chymist. London: J. Cadwell for J. Crooke.
- Lavoisier, A.-L. (1789). Traité élémentaire de chimie. Paris: Cuchet.
- Dalton, J. (1808). A New System of Chemical Philosophy, Part I. Manchester: R. Bickerstaff.
- Mendeleev, D. I. (1869). Sootnoshenie svoistv s atomnym vesom elementov [The relation between the properties and atomic weights of the elements]. Zhurnal Russkogo Khimicheskogo Obshchestva, 1, 60–77.
- Rutherford, E. (1911). The scattering of α and β particles by matter and the structure of the atom. Philosophical Magazine, 21(125), 669–688.
- Moseley, H. G. J. (1913). The high-frequency spectra of the elements. Philosophical Magazine, 26(156), 1024–1034.
- Seaborg, G. T. (1945). The chemical and radioactive properties of the heavy elements. Chemical & Engineering News, 23(23), 2190–2193.
- Burbidge, E. M., Burbidge, G. R., Fowler, W. A., & Hoyle, F. (1957). Synthesis of the elements in stars. Reviews of Modern Physics, 29(4), 547–650.
- Oganessian, Yu. Ts., et al. (2006). Synthesis of the isotopes of elements 118 and 116 in the 249Cf and 245Cm + 48Ca fusion reactions. Physical Review C, 74(4), 044602.