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Medical Term:


Pronunciation: e-lek'tron


One of the negatively charged subatomic particles that orbit the positive nucleus, in one of several energy levels called shells; in mass they are estimated to be 1/1836.15 of a proton; when emitted from inside the nucleus of a radioactive substance, electrons are called ß particles. A nucleus and its electrons constitute an atom.

[electro- + -on]

See Also: shell

© Copyright 2017 Wolters Kluwer. All Rights Reserved. Review Date: Sep 19, 2016.