atomic weight

atomic weight

n.

The average mass of an atom of an element, usually expressed relative to the mass of carbon 12, which is assigned 12 atomic mass units.

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atomic weight

Noun

the ratio of the average mass per atom of an element to one twelfth of the mass of an atom of carbon-12

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atomic weight

The mass of an atom expressed in atomic mass units. The atomic weight of an element having more than one principal isotope is calculated both from the atomic masses of the isotopes and from the relative abundance of each isotope in nature. For example, the atomic weight of the element chlorine is 35.453, determined by averaging the atomic masses and relative abundances of its two main naturally occurring isotopes, which have atomic masses of about 35 and 37. Also called relative atomic mass. Compare atomic mass. See also mass number.

Thesaurus

Noun

1.

atomic weight - (chemistry) the mass of an atom of a chemical element expressed in atomic mass units atomic mass, relative atomic mass mass - the property of a body that causes it to have weight in a gravitational field combining weight, eq, equivalent weight, equivalent - the atomic weight of an element that has the same combining capacity as a given weight of another element; the standard is 8 for oxygen meq, milliequivalent - one-thousandth of an equivalent chemical science, chemistry - the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions