Atomic mass unit (u)
Definition: An atomic mass unit (symbol: u), also called the unified atomic mass unit, is defined as one twelfth of the mass of a carbon-12 atom. It is an extremely small unit used in atomic and molecular science.
History/origin: The atomic mass unit was developed so chemists and physicists could compare the masses of atoms and molecules using a practical relative standard rather than kilograms.
Current use: Atomic mass units are used in chemistry, nuclear physics, and molecular science to express the mass of atoms, isotopes, and molecules.
