Dalton (unit)

unit of mass defined as ¹⁄₁₂ of the mass of a carbon-12 atom

The dalton or unified atomic mass unit, abbreviated as u, amu or Da) is a unit of measurement that is used to measure the mass of atoms, equalling ¹⁄₁₂ of the mass of the carbon-12 isotope, the most abundant form of carbon atoms in nature.[1][2][3] The unit is named after English chemist and physicst John Dalton (1766–1844). 1 atomic mass unit is approximately 1.66 × 10-27 kg, or 1.66 × 10-24 g.[4]

In atomic physics, 1 amu is expressible as roughly 931 MeV (M = 106, 1 eV ≈ 1.60 × 10-19 J) due to mass-energy equivalence, illustrated by ΔE = Δmc2.[5][6]

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References

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  1. Mills, Ian; Cvitaš, Tomislav; Homann, Klaus; Kallay, Nikola; Kuchitsu, Kozo (1993). Quantities, Units and Symbols in Physical Chemistry International Union of Pure and Applied Chemistry; Physical Chemistry Division (PDF) (2nd ed.). International Union of Pure and Applied Chemistry and published for them by Blackwell Science Ltd. ISBN 0-632-03583-8.
  2. "Consultative Committee for Units (CCU); Report of the 15th meeting (17 –18 April 2003) to the International Committee for Weights and Measures" (PDF). Archived from the original (PDF) on 7 June 2011. Retrieved 14 Aug 2010.
  3. "IU14. IUPAC Interdivisional Committee on Nomenclature and Symbols (ICTNS)". Archived from the original on 2011-06-14. Retrieved 2010-08-14.
  4. "Atomic mass unit | Definition, Description, Uses, & Facts". Britannica. November 11, 2024. Retrieved November 30, 2024.
  5. "Converted number: Conversion from eV to J". National Institute of Standards and Technology (NIST). 2022. Retrieved November 30, 2024.
  6. "Nuclear Binding Energy and the Mass Defect". Boston University. Retrieved November 30, 2024.