Smallest particle still characterizing a chemical element
. It consists of a nucleus
of a positive charge
is the proton number
the elementary charge
) carrying almost all its mass (more than 99.9%) and
electrons determining its size.
Physical Chemistry Division, unpublished
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook