electron

electron Elementary particle of mass 9.11 × 10⁻³¹kg and negative electrical charge of 1.602×10⁻¹⁹C (coulombs). Electrons can exist independently, or in groups around the nucleus of an atom. Experiments show that electrons in an atom may occur at a range of distances from the nucleus but are most likely to exist in certain low-energy orbits or shells, and within these shells there are further subshells, the configuration being such that no two electrons in any one atom have identical properties. When an electron moves from one subshell to another of lower energy, electromagnetic radiation is given off; if an electron moves to a subshell of higher energy, electromagnetic radiation is absorbed. An electron moves about the nucleus in a circular or elliptical orbit and also spins on its axis.