Kern NMR alpha particle antibaryon antilepton antimeson atomic nucleus atomic particle aurora particle baryon cathode particle electron electron affinity electron cloud electron pair electron shells electron spin electron transfer electron-positron pair elementary particle energy level excited state extranuclear electrons ground state heavy particle lepton lone pair meson mesotron negatron neutron nuclear force nuclear magnetic resonance nuclear particle nuclear resonance nucleon nucleosynthesis nucleus octet orbital electron photoelectron photon proton radioactive particle radion recoil electron secondary electron shared pair solar particle strangeness strong interaction subvalent electrons surface-bound electron thermion triton valence electron valence electrons valence shell wandering electron