What radioactive isotopes are naturally occurring?

1 Answer
Judy O.
Apr 6, 2014

This is a list of all the naturally occurring elements which either have no stable isotopes, or have at least one naturally occurring isotope that is radioactive.

Potassium K^19
Technetium Tc^43
Cadmium Cd^48
Promethium Pm^61
Polonium Po^84
Astatine At^85
Radon Rn^86
Francium Fr^87
Radium Ra^86
Actinium Ac^89
Uranium U^92

93-118 are not naturally occurring but are radioactive.
110-118 have not been named yet.

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