The electron is a fundamental subatomic particle that was identified and assigned the negative charge in 1897 by J.J. Thomson and his team of British physicists. These electrically-charged particles, together with the protons and neutrons that comprise atomic nuclei, make up atoms. Electron–electron interaction between atoms is the main cause of chemical bonding. Electrons also play an essential role in electricity and magnetism.

All electrons are identical particles that belong to the first generation of the lepton particle family. Each electron carries a negative elementary charge and participates in electromagnetic and weak interactions. It has a property of intrinsic angular momentum called spin, with a standardized value of frac: 2. The mass of an electron is approximately frac: 1836 of that of the proton, and it is believed to be a point particle with no apparent substructure. The properties of the electron are determined by its interaction with other particles.

Etymology

The English name electron is a combination of the word electric and the suffix -on, with the latter now used to designate a subatomic particle. Both electric and electricity are derived from the Latin ēlectrum, which in turn came from the Greek word ēlektron (ήλεκτρον) for amber; a gemstone that is formed from the hardened sap of trees (the ancient Greeks noticed that amber, when rubbed with fur, attracted small objects). Apart from lightning this phenomenon was man's earliest experience of electricity.

History

main: History of electromagnetism

As early as 1838–51, the British natural philosopher Richard Laming conceived the idea that an atom is composed of a core of matter surrounded by subatomic particles that had unit electrical charges. Beginning in 1846, German physicist William Weber theorized that electricity was composed of positively and negatively charged fluids, and their interaction was governed by the inverse square law. After studying the phenomenon of electrolysis in 1874, the Anglo-Irish physicist G. Johnstone Stoney suggested that there existed a "single definite quantity of electricity." He was able to estimate the value of the charge e of a monovalent ion by means of Faraday's laws of electrolysis. However, Stoney believed these charges were permanently attached to atoms and could not be removed. In 1881, German physicist Hermann von Helmholtz argued that both positive and negative charges were divided into elementary parts, each of which "behaves like atoms of electricity".

In 1894, Stoney coined the term electron to represent these elementary charges.