Relative atomic mass (symbol: Ar) is a dimensionless physical quantity, the ratio of the average mass of atoms of an element (from a given source) to 1/12 of the mass of an atom of carbon-12 (known as the unified atomic mass unit). The term is usually used, without further qualification, to refer to the standard atomic weights published at regular intervals by the International Union of Pure and Applied Chemistry (IUPAC) and which are intended to be applicable to normal laboratory materials. These standard atomic weights are reprinted in a wide variety of textbooks, commercial catalogues, wallcharts etc., and in the table below.
The term "atomic weight" (of the element) is also used to describe this physical quantity, and is synonymous with it. However, its continued use has attracted considerable controversy since at least the 1960s (see below).
Read more about Relative Atomic Mass: Definition, Naming Controversy, Determination of Atomic Weight, Periodic Table With Atomic Weights
Famous quotes containing the words relative, atomic and/or mass:
“It is an interesting question how far men would retain their relative rank if they were divested of their clothes.”
—Henry David Thoreau (1817–1862)
“It is now time to stop and to ask ourselves the question which my last commanding officer, Admiral Hyman Rickover, asked me and every other young naval officer who serves or has served in an atomic submarine. For our Nation M for all of us M that question is, “Why not the best?””
—Jimmy Carter (James Earl Carter, Jr.)
“What will happen once the authentic mass man takes over, we do not know yet, although it may be a fair guess that he will have more in common with the meticulous, calculated correctness of Himmler than with the hysterical fanaticism of Hitler, will more resemble the stubborn dullness of Molotov than the sensual vindictive cruelty of Stalin.”
—Hannah Arendt (1906–1975)