Electron

Electron

Hydrogen atomic orbitals at different energy levels. The more opaque areas are where one is most likely to find an electron at any given time.
Composition	Elementary particle[1]
Statistics	Fermionic
Family	Lepton
Generation	First
Interactions	Weak, electromagnetic, gravity
Symbol	e− , β−
Antiparticle	Positron[a]
Theorized	Richard Laming (1838–1851),[2] G. Johnstone Stoney (1874) and others.[3][4]
Discovered	J. J. Thomson (1897)[5]
Mass	9.1093837139(28)×10−31 kg‍[6] 5.485799090441(97)×10−4 Da‍[7] [1822.888486209(53)]−1 Da[b] 0.51099895069(16) MeV/c2‍[8]
Mean lifetime	> 6.6×1028 years[9] (stable)
Electric charge	−1 e −1.602176634×10−19 C‍[10]
Magnetic moment	−9.2847646917(29)×10−24 J⋅T−1‍[11] −1.00115965218128(18) μB[12]
Spin	⁠ 1 /2⁠ ħ
Weak isospin	LH: −⁠ 1 /2⁠, RH: 0
Weak hypercharge	LH: −1, RH: −2

Standard Model of particle physics
Elementary particles of the Standard Model
Background Particle physics Standard Model Quantum field theory Gauge theory Spontaneous symmetry breaking Higgs mechanism
Constituents Electroweak interaction Quantum chromodynamics CKM matrix Standard Model mathematics
Limitations Strong CP problem Hierarchy problem Neutrino oscillations Physics beyond the Standard Model
Scientists Rutherford Thomson Chadwick Bose Sudarshan Davis Jr Anderson Fermi Dirac Feynman Rubbia Gell-Mann Kendall Taylor Friedman Powell Anderson Glashow Iliopoulos Lederman Maiani Meer Cowan Nambu Chamberlain Cabibbo Schwartz Perl Majorana Weinberg Lee Ward Salam Kobayashi Maskawa Mills Yang Yukawa 't Hooft Veltman Gross Pais Pauli Politzer Reines Schwinger Wilczek Cronin Fitch Vleck Higgs Englert Brout Hagen Guralnik Kibble de Mayolo Lattes Zweig
v t e

The electron (
e⁻
, or
β⁻
in nuclear reactions) is a subatomic particle with a negative one elementary electric charge.^[13] Electrons belong to the first generation of the lepton particle family,^[14] and are generally thought to be elementary particles because they have no known components or substructure.^[1] The electron's mass is approximately ⁠1/1836⁠ that of the proton.^[15] Quantum mechanical properties of the electron include an intrinsic angular momentum (spin) of a half-integer value, expressed in units of the reduced Planck constant, ħ. Being fermions, no two electrons can occupy the same quantum state, per the Pauli exclusion principle.^[14] Like all elementary particles, electrons exhibit properties of both particles and waves: They can collide with other particles and can be diffracted like light. The wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Broglie wavelength for a given energy.

Electrons play an essential role in numerous physical phenomena, such as electricity, magnetism, chemistry, and thermal conductivity; they also participate in gravitational, electromagnetic, and weak interactions.^[16] Since an electron has charge, it has a surrounding electric field; if that electron is moving relative to an observer, the observer will observe it to generate a magnetic field. Electromagnetic fields produced from other sources will affect the motion of an electron according to the Lorentz force law. Electrons radiate or absorb energy in the form of photons when they are accelerated.

Laboratory instruments are capable of trapping individual electrons as well as electron plasma by the use of electromagnetic fields. Special telescopes can detect electron plasma in outer space. Electrons are involved in many applications, such as tribology or frictional charging, electrolysis, electrochemistry, battery technologies, electronics, welding, cathode-ray tubes, photoelectricity, photovoltaic solar panels, electron microscopes, radiation therapy, lasers, gaseous ionization detectors, and particle accelerators.

Interactions involving electrons with other subatomic particles are of interest in fields such as chemistry and nuclear physics. The Coulomb force interaction between the positive protons within atomic nuclei and the negative electrons without allows the composition of the two known as atoms. Ionization or differences in the proportions of negative electrons versus positive nuclei changes the binding energy of an atomic system. The exchange or sharing of the electrons between two or more atoms is the main cause of chemical bonding.^[17]

In 1838, British natural philosopher Richard Laming first hypothesized the concept of an indivisible quantity of electric charge to explain the chemical properties of atoms.^[3] Irish physicist George Johnstone Stoney named this charge "electron" in 1891, and J. J. Thomson and his team of British physicists identified it as a particle in 1897 during the cathode-ray tube experiment.^[5]

Electrons participate in nuclear reactions, such as nucleosynthesis in stars, where they are known as beta particles. Electrons can be created through beta decay of radioactive isotopes and in high-energy collisions, for instance, when cosmic rays enter the atmosphere. The antiparticle of the electron is called the positron; it is identical to the electron, except that it carries electrical charge of the opposite sign. When an electron collides with a positron, both particles can be annihilated, producing gamma ray photons.

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