Proton: postiviely charged subatomic particle in nucleus of atom, responsable for atomic number of substance, used with neutrons to find atomic mass.
Neutron: neutral charged subatomic particle in nucleus of atom, used with protons to find atomic mass, differences between atoms with same number of protons but different neutrons result in isotopes.
Isotope: atoms with different numbers of neutrons and atomic masses, but same number of protons
Atomic mass: number of protons and number of neutrons
Radioactive: unstable isotopes release ionized particles as nucleus decays
Natural abundance: relative comparison of isotopes as they occur in nature
