The trite phrase "the 92 naturally-occurring chemical elements" is often seen, but is incorrect. There are only 88 naturally-occurring chemical elements. The elements 43, 61, 85 and 87 have no stable isotopes, and none of long half-life, so they are not naturally present. Small amounts are made in nuclear reactions induced by cosmic rays and nuclear tests, but these soon disappear. If you protest that these should be included, then so should Np and Pu, which are produced by the absorption of neutrons arising from spontaneous fission of uranium and thorium, and then there would be 94 naturally-occurring elements. If you wait long enough, there will only be 81 naturally-occurring elements, since everything beyond lead has only unstable isotopes, though some are of very long half-life, and have survived since the beginning, fathering their radioactive series. Any way you look at it, there are not just 92 naturally-occurring chemical elements.
Composed by J. B. Calvert
Created 6 May 2003