ATOMIC MASS Definition & Meaning

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atomic mass

[ uh-tom-ik mas ]

Phonetic (Standard)IPA

noun

Chemistry.

the mass of an isotope of an element measured in units formerly based on the mass of one hydrogen atom taken as a unit or on 1/16 (0.0625) the mass of one oxygen atom, but after 1961 based on 1/12 (0.0833) the mass of the carbon-12 atom.

atomic mass

noun

the mass of an isotope of an element in atomic mass units
short for relative atomic mass See atomic weight

atomic mass

The mass of a given atom or molecule, expressed in atomic mass units.
Compare atomic weightSee also mass number

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�y��vlog History and Origins

Origin of atomic mass¹

First recorded in 1895–1900

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How does atomic mass compare to similar and commonly confused words? Explore the most common comparisons:

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Example Sentences

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"Many thousands of atomic nuclei that have yet to be measured may exist in nature," said Matthew Mumpower, a theoretical physicist and co-author on several recent papers detailing atomic masses research.

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The team was able to determine that the r-process can produce atoms with an atomic mass of at least 260 before they fission.

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Wallner is particularly interested in the radioactive iron isotope with the atomic mass of 60.

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Twelve, named for the atomic mass of carbon, has developed a process to make jet fuel using renewable electricity, water and waste biomass CO2 instead of fossil fuels.

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A silvery, alkaline earth metal called strontium comes in different versions, or isotopes, each with a different atomic mass.

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