An electron is a negatively charged component of an atom.
Share. Electron Definition: An electron is a negatively charged component of an atom. Electrons exist outside of and surrounding the atom nucleus. Each electron carries one unit of negative charge and has a very small mass as compared with that of a neutron or proton. By Anne Marie Helmenstine, Ph.D electron, An elementary particle that orbits the nucleus of an atom. There is one electron for every proton in the nucleus, which keeps the atom electrically neutral, as electrons are considered to have a negative charge and protons a positive charge. elementary particle elementary particles,the most basic physical constituents of the universe. Basic Constituents of Matter Molecules are built up from the atom, which is the basic unit of any chemical element. The atom in turn is made from the proton, neutron, and electron...... electron. any of the negatively charged particles arranged in orbitals around the nucleus of an atom and determining all of the atom's physical and chemical properties except mass and radioactivity.  Definition of electron. 1) A subatomic particle having a mass of 0.00054858 amu and a charge of 1-. 2) A particle of matter that has a negative electric charge of 4.8 E -10 esu and a mass of 9.1E -28g or 1/1837 the mass of a proton.  LINK / CITE ADD TO WORD LIST. noun. The definition of an electron is the lightest basic electrically-charged particle. An example of an electron is what orbits the nucleus of an atom.  Electron Cloud Definition: The region of negative charge surrounding an atomic nucleus that is associated with an atomic orbital. By Anne Marie Helmenstine, Ph.D.  Noun. 1. electron shell-a grouping of electrons surrounding the nucleus of an atom; the chemical properties of an atom are determined by the outermost electron shell. group, grouping-any number of entities (members) considered as a unit.  noun. A stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids. Example sentences. 1  The antiparticle of the electron is the positron; there are also antiquarks and antineutrinos.  e•lec•tron. 1. an elementary particle that is a fundamental constituent of matter, having a negative charge of 1.602 x 10 −19 coulombs, and existing independently or as the component outside the nucleus of an atom. 2. a unit of charge equal to the charge on one electron. 
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definition of an electron