The atomic mass (ma) is the mass of specific isotope of a given atom, most often expressed in unified atomic mass units. The atomic mass may be considered to be the total mass of protons, neutrons and electrons in a single atom (when the atom is motionless). The atomic mass is sometimes incorrectly used as a synonym of relative atomic mass, average atomic mass and atomic weight; these differ subtly from the atomic mass. The atomic mass is defined as the mass of an atom, which can only be one isotope at a time and is not an abundance-weighted average as in the case of atomic weight. In the case of many elements that have one dominant isotope the actual numerical similarity/difference between the atomic mass of the most common isotope and the relative atomic mass or standard atomic weights can be very small such that it does not affect most bulk calculations - but such an error can be critical when considering individual atoms. For elements with more than one common isotope the difference even to the most common atomic mass can be half a mass unit or more (e.g. chlorine). The atomic mass of an uncommon isotope can differ from the relative atomic mass or standard atomic weight by several mass units. [Wikipedia]
See Also
atomic Atomic Force atomic weight Chord of Mass chord of the mass Figure 5.10 - Introductory Degeneration of Mass via Interpenetrating Vortices Figure 5.8 - Initiatory Generation of Mass via Interpenetrating Vortices Figure 5.9 - Initiatory Generation of Mass and Sphericity Figure 13.06 - Atomic Subdivision Figure 16.02 - Electricity Evolves Mass into Spheres Force-Atomic InterAtomic Law of Oscillating Atomic Substances Light Units mass Mass Chord molecular mass 3.14 - Vortex Theory of Atomic Motions 5.7 - Generation of Mass 5.8 - Degeneration of Mass 12.39 - Mass 13.04 - Atomic Subdivision