the mass of the atom is determined by protons and neutrons
nickel_atom is atom. electrons_protons_and_neutrons is smaller_than_atoms. atoms has electrons hydrogen_atoms has one_proton_and_one_electron phosphorus_atom is atom. hydrogen_atom is atom. neutrons has about_as_much_mass_as_protons atoms has mass protons is component_of_atoms. atomic_mass is mass.