ATOMIC & NUCLEAR PHYSICS PARTICLE PHYSICS ELECTRICITY & MAGNETISM A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z           HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site electron Electron tracks. Credit: CERN A negatively charged subatomic particle with a mass equal to 1/1837 that of a proton or about 9 × 10-31 kg. Very roughly, a trillion electrons would weigh about as much as a speck of dust. Electrons are fermions. Like all other fermions, the electron has no known internal structure. It behaves as if it has zero radius. The antiparticle of the electron is the positron. Fast moving streams of electrons emitted during radioactive decay are known as beta particles. Electrons occur in the outer parts of atoms, in orbitals corresponding to definite fixed energies. When an electron in an atom jumps from one particular orbital to another it gives rise to the emission or absorption of electromagnetic radiation at a specific characteristic wavelength. All chemical properties of atoms and molecules are determined by the electric interactions of electrons with each other and with the atomic nuclei. The name "electron" was first suggested by G. Johnstone Stoney in 1891 for the natural unit of electricity. The particle that plays this role was discovered by J. J. Thomson in 1897. "Electron", "electricity", etc, derive from the term "electrica", coined by W. Gilbert in 1600 to denote substances such as amber (electrum in Greek) that attract light objects when rubbed. Related categories    • ATOMIC AND NUCLEAR PHYSICS    • PARTICLE PHYSICS    • ELECTRICITY AND MAGNETISM    • PHYSICAL CHEMISTRY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP