Electron

The electron is a subatomic particle that carries a negative electrical charge. It is an elementary particle with no known substructure and is believed to be a point particle.[2] Each electron participates in gravitational, electromagnetic and weak interactions. The mass of an electron is approximately 1⁄1836 of a proton. Like its rest mass and elementary charge, the intrinsic angular momentum (or spin) of an electron has a constant value. In the collision of an electron and a positron, the electron's antiparticle, both are annihilated. An electron–positron pair can be produced from gamma ray photons with a combined energy at least equal to the energy at rest of the particles.[8]

Electrons are identical particles that belong to the first generation of the lepton particle family. Electrons have quantum mechanical properties of both a particle and a wave, so they can collide with other particles and be diffracted like light. Each electron occupies a quantum state that describes its random behavior upon measuring a physical parameter, such as its energy or spin orientation. Because they are a type of fermion, no two electrons can occupy the same quantum state; a property known as the Pauli exclusion principle.[9]

In order to explain the chemical properties of atoms, the concept of an indivisible amount of electrical charge was theorized on several occasions, beginning in 1838 by British natural philosopher Richard Laming;[4] the name electron was introduced for this charge in 1894 by Irish physicist George Johnstone Stoney. The electron was first identified as a particle in 1897 by J. J. Thomson and his team of British physicists.[6][10] Electrons play an essential role in many physical phenomena such as electricity, magnetism, and thermal conductivity. When an electron is in motion, it both generates a magnetic field and is deflected by external magnetic fields. While an electron is undergoing acceleration, it can absorb or radiate energy in the form of photons. Electrons, together with atomic nuclei made of protons and neutrons, make up atoms. The attractive Coulomb force between an electron and a proton is what causes electrons to be bound into atoms. The exchange, sharing or interaction of the electrons in two or more atoms is the main cause of chemical bonding.[11]