Atomic mass and atomic mass unit
- Atomic mass is the total of the masses of the electrons, neutrons, and protons in an atom, or in a group of atoms, the average mass.
- Mass of an atomic particle is called the atomic mass.
- This is commonly expressed as per the international agreement in terms of a unified atomic mass unit (AMU).
- It can be best defined as 1/12 of the mass of a carbon-12 atom in its ground state.