elektron

The elektron, or electron, is a subatomic particle with negative electric charge. It is a member of the lepton family and is considered elementary in the Standard Model, meaning it is not known to be composed of smaller parts. The electron has a rest mass of about 9.11 × 10^-31 kilograms (approximately 0.511 MeV/c^2 in energy units) and a intrinsic angular momentum, or spin, of 1/2. Its charge is a single elementary unit, negative in sign, and it interacts with the electromagnetic force and, via the weak interaction, with other fundamental forces. It does not participate in the strong interaction.

Historically, the electron was discovered in 1897 by J. J. Thomson through cathode-ray experiments that revealed a negatively charged particle much lighter than atoms. The magnitude of the electron’s charge was later measured by Robert A. Millikan in his oil-drop experiment, establishing the elementary charge as a fundamental constant. The electron's behavior is described by quantum mechanics; relativistic treatment is provided by the Dirac equation. In quantum electrodynamics, electrons interact with photons, and precise calculations using Feynman diagrams account for a wide range of phenomena.

In atoms, electrons occupy orbitals around the nucleus and determine chemical properties through their arrangement and bonding capabilities. They serve as the primary carriers of electricity in metals and play a crucial role in a vast array of physical, chemical, and technological processes. The electron has a positively charged antiparticle, the positron (antielectron), discovered in 1932.