Define one atomic mass unit (a.m.u.).

Atomic mass unit:

• An atomic mass unit (a.m.u or u) is a measure used to talk about how heavy atoms are. It’s defined as 1/12th the mass of a carbon-12 atom.
• Carbon-12 is a type of carbon atom. It has six tiny particles called neutrons and six particles called protons in its center.
• This unit helps scientists talk about the mass of atoms. For example, 1 a.m.u is like the average mass of a proton and a neutron.
• 1 a.m.u. = 1.67377 x 10^-27 kilogram or 1.67377 x 10^-24 gram.