Particle Isotope Mole Compound
1/1800 a.m.u. 1/2 a.m.u. 1 a.m.u. 10 a.m.u.
Protons Electrons Neither Neutrons
Neither Electron Proton Neutron
In random energy levels In discrete energy levels 1 circular orbit Totally randomly
Beryllium Helium Hydrogen Lithium