Question

Is most of an atoms mass found in protons and neutrons?

Answer 1

Yes, most of an atom's mass is found in the protons and neutrons that make up its nucleus. Protons and neutrons have approximately the same mass, with each proton and neutron having a mass of around 1 atomic mass unit (amu). In comparison, electrons have a much smaller mass, about 1/1836 amu. Therefore, the mass of the electrons is usually considered negligible when calculating the total mass of an atom.