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Glite Dictionary
atomic mass unit

atomic mass unit

3.9
A small unit for mass used to measure atoms and molecules
  • noun
  • /əˈtɑːmɪk mæs juːnɪt/
  • Specialized
translation icon : unidad de masa atómica
  • Carbon dioxide (CO2) isotopologues can have masses of 44, 45, or 46 atomic mass units, depending on the nuclides that compose them.

Examples

  • As can be seen in the accompanying figure, the most abundant compound produced was SO2, which was tracked by its SO+ fragment ion at a mass-to-charge ratio m/z of 48 atomic mass units.

    Academic text (1998)

  • With a molecular weight of only 14.7 kilodaltons (1 dalton = 1 atomic mass unit), these dimers are among the smallest proteins imaged by any kind of microscopy.

    Academic text (1995)

  • So you can see the atomic mass unit will then give you that the atomic mass unit will be one point.

  • Proteins, for example, can range from a few thousand atomic mass units (daltons), such as for the hormone insulin, to more than 5 million Da for large enzyme complexes.

    Academic text (2002)

  • Carbon has an atomic mass of exactly 12.0 atomic mass units, which is useful for calculations in chemistry.

  • The average mass of an element is expressed in atomic mass units to standardize measurements in scientific research.

  • A molecule's mass can be measured in atomic mass units, making it easier to compare different substances.

Synonyms

dalton
vsatomic mass unit
  • Specialized
1 7.4

A small unit for measuring the mass of atoms and molecules

has identical meaning but is the fuller descriptive term not the short name

Surface Forms

atomic mass unit singular
atomic mass units plural

Morphology

atomic + mass + unit

The phrase is fully compositional: 'atomic' specifies 'of atoms', 'mass' names the property measured, and 'unit' signals a measurement standard, so the meaning ‘a measurement unit for the mass of atoms’ is directly derivable from the parts. Scientific naming is regular and parallels exist across languages, making this immediately understandable to a learner who knows the constituent words.

Etymology

The term atomic mass unit comes from making a small, simple unit to measure the mass of an atom. Scientists set it to the size of 'one twelfth of a carbon-12 atom' so an atom's weight becomes a small, easy number of atomic mass units, and that is why we use it to measure atoms and tiny particles.