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)
“Other centuries had their driving forces. What will ours have been when men look far back to it one day? Maybe it won’t be the American Century, after all. Or the Russian Century or the Atomic Century. Wouldn’t it be wonderful, Phil, if it turned out to be everybody’s century, when people all over the world—free people—found a way to live together? I’d like to be around to see some of that, even the beginning.”
—Moss Hart (1904–1961)
“The pathetic thing about the great wellintentioned mass of college and highschool students is that they have been so badly educated they have no knowledge or understanding of the complications of the world we live in and they have been so conditioned and prejudiced by generations of ill-taught teachers that they refuse to see a fact when they are confronted with one.”
—John Dos Passos (1896–1970)