Isotone Isotone Two nuclides are isotones if they have the same neutron number "N", but different proton number "Z". For example, boron-12 and carbon-13 nuclei both contain 7 neutrons, and so are isotones. Similarly, S, Cl, Ar, K, and Ca nuclei are all isotones of 20 because they all contain 20 neutrons. Despite its similarity to the Greek for "same stretching", the term was formed by the German physicist K. Guggenheimer by changing the "p" in "isotope" from "p" for "proton" to "n" for "neutron". The largest numbers of observationally stable nuclides exist for isotones 50 (five: Kr, Sr, Y, Zr,
Atomic theory emitted from the gas (Rutherford recognized these, because he had previously obtained them bombarding hydrogen with alpha particles, and observing hydrogen nuclei in the products). Rutherford concluded that the hydrogen nuclei emerged from the nuclei of the nitrogen atoms themselves (in effect, he had split a nitrogen). From his own work and the work of his students Bohr and Henry Moseley, Rutherford knew that the positive charge of any atom could always be equated to that of an integer number of hydrogen nuclei. This, coupled with the atomic mass of many elements being roughly equivalent to an integer number of