Isotop
Dalam nomenklatur ilmiah, isotop (nuklida) dispesifikasikan berdasarkan nama unsur tertentu oleh sebuah hyphen dan jumlah nukleon (proton dan neutron) dalam nukleus atom (misal, helium-3, karbon-12, karbon-14, besi-57, uranium-238). Dalam bentuk simbolik, jumlah nukleon ditandakan sebagai sebuah prefik naik-ke-atas terhadap simbol kimia (misal, He, C, C, Fe, U, dan lain-lain).
Neutrino elektron
Dear radioactive ladies and gentlemen,
As the bearer of these lines [...] will explain more exactly, considering the 'false' statistics of N-14 and Li-6 nuclei, as well as the continuous "β"-spectrum, I have hit upon a desperate remedy to save the "exchange theorem" of statistics and the energy theorem. Namely [there is] the possibility that there could exist in the nuclei electrically neutral particles that I wish to call neutrons, which have spin 1/2 and obey the exclusion principle, and additionally differ from light quanta in that they do not travel with the velocity of light: The mass of the neutron must be of the same order of magnitude as the electron mass and, in any case, not larger than 0.01 proton mass. The continuous "β"-spectrum would then become understandable by the assumption that in "β" decay a neutron is emitted together with the electron, in such a way that the sum of the energies of neutron and electron is constant.[...]But I don't feel secure enough to publish anything about this idea, so I first turn confidently to you, dear radioactives, with a question as to the situation concerning experimental proof of such a neutron, if it has something like about 10 times the penetrating capacity of a "γ" ray.I admit that my remedy may appear to have a small "a priori" probability because neutrons, if they exist, would probably have long ago been seen. However, only those who wager can win, and the seriousness of the situation of the continuous "β"-spectrum can be made clear by the saying of my honored predecessor in office, Mr. Debye, [...] "One does best not to think about that at all, like the new taxes." [...] So, dear radioactives, put it to test and set it right. [...]With many greetings to you, also to Mr. Back, your devoted servant,