Atoms and Molecules

Structure of the Atom

What is an atomic mass unit?

One atomic mass unit has a mass of 1.66 × 10−27 kg, which is about the mass of a single proton or neutron. These units are convenient, since when the mass of atoms is expressed in atomic mass units, their masses come out to values that are very close to integers. The values of mass given on the periodic table are expressed in atomic mass units.


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