Answer:
carbon-12
Step-by-step explanation:
- One atomic mass unit is defined as a mass exactly equal to one-twelfth the mass of one carbon-12 atom. Carbon-12 is the carbon isotope that has six protons and six neutrons.
- A single atom's atomic mass is just its total mass, which is usually given in atomic mass units, or amu. An atom of carbon with six neutrons, carbon-12, has an atomic mass of 12 amu by definition.
- An atomic mass unit (abbreviated as AMU or amu) is defined as 1/12 the mass of a carbon-12 atom. The nucleus of the carbon-12 (C-12) atom contains six protons and six neutrons. One AMU is the average of the proton and neutron rest masses, in approximate words.
- This equates to about 1.67377 x 10 -27 kilogram (kg) or 1.67377 x 10 -24 gram (g). In AMU, an atom's mass is generally equal to the nucleus' total amount of protons and neutrons.
- The AMU is used to express and differentiate between various isotopes of elements by expressing their relative masses. Thus, uranium-235 (U-235) has an AMU of roughly 235, but uranium-238 (U-238) has a little higher AMU. The disparity is due to the fact that U-238, the most common naturally occurring uranium isotope, contains three more neutrons than U-235, which has been utilized in nuclear reactors and atomic bombs.