unit atomic mass (Unified Atomic Mass Unit) are usually brief, to form the amu or u Dalton (dalton, etc. the symbol Da) is a measure for the mass scale of atomic or . That for one-twelfth the mass of an atom of carbon-12 in the normal mode be known that against 1.660538921(73)×10-27 kg.
This YK with almost the mass of a neutron or proton is equal and the difference amount because of the difference, Jeremy, is that the energy depends on the core can be transformed.