If you had only one atom of an element, say boron, and can monitor it closely without alteration, considering the quantum fluctuations in the existence and location of elections, protons, neutrons, and the quarks, is one atom of boron always boron, or over some period of time can boron become beryllium or carbon with out emission or gain of subatomic particles or photons. Or is one atom of boron always an atom of boron for eternity - excluding things like proton decay.