Isotopes of tin

Tin (₅₀Sn) is the element with the greatest number of stable isotopes (ten; three of them are potentially radioactive but have not been observed to decay). Moreover, tin is not only the element with the greatest number of observationally stable isotopes, but also the element with the greatest number of theoretically stable isotopes (it is the only one element with seven theoretically stable isotopes, all other elements have at most five theoretically stable isotopes, the elements with five theoretically stable isotopes are titanium, ruthenium, xenon, and barium). This is probably related to the fact that 50 is a "magic number" of protons. In addition, twenty-nine unstable tin isotopes are known, including tin-100 (¹⁰⁰Sn) (discovered in 1994) and tin-132 (¹³²Sn), which are both "doubly magic". The longest-lived tin radioisotope is tin-126 (¹²⁶Sn), with a half-life of 230,000 years. The other 28 radioisotopes have half-lives of less than a year.