Which best describes the mass of protons, neutrons and electrons

atom: The smallest possible amount of matter which still retains its identity as a chemical element, consisting of a nucleus surrounded by electrons.

proton: Positively charged subatomic particle forming part of the nucleus of an atom and determining the atomic number of an element. It weighs 1 amu.

neutron: A subatomic particle forming part of the nucleus of an atom. It has no charge. It is equal in mass to a proton or it weighs 1 amu.

Protons = 1 AMU (Atomic Mass Unit)

Neutrons = 1 AMU

Electrons = 1/1800 AMU (Much smaller than protons and neutrons)