https://doi.org/10.1351/goldbook.A00493
Smallest particle still characterizing a @[email protected] It consists of a @[email protected] of a positive charge (\(Z\) is the @[email protected] and \(e\) the @[email protected]) carrying almost all its mass (more than 99.9%) and \(Z\) electrons determining its size.
Source:
Red Book, 3rd ed., p. 35 [Terms] [Book]