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,
Discovery of the neutron show that neutrons interacting with nitrogen nuclei scattered to protons or induced nitrogen to disintegrate to form boron with the emission of an alpha particle. Feather was therefore the first to show that neutrons produce nuclear disintegrations. In Rome, Enrico Fermi bombarded heavier elements with neutrons and found the products to be radioactive. By 1934 Fermi had used neutrons to induce radioactivity in 22 different elements, many of these elements of high atomic number. Noticing that other experiments with neutrons at his laboratory seemed to work better on a wooden table than a marble table, Fermi suspected that the protons