the mass of the atom is determined by protons and neutrons
phosphorus_atom is atom. neutrons has about_as_much_mass_as_protons electrons_protons_and_neutrons is not smaller_than_atoms. neutrons has not about_as_much_mass_as_protons atomic_mass is mass. protons is not component_of_atoms. protons is component_of_atoms. atoms has mass electrons_protons_and_neutrons is smaller_than_atoms. nickel_atom is atom.