# What radioactive isotopes are naturally occurring?

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 $T {c}^{43}$
Cadmium $C {d}^{48}$
Promethium $P {m}^{61}$
Polonium $P {o}^{84}$
Astatine $A {t}^{85}$
Radon $R {n}^{86}$
Francium $F {r}^{87}$
Radium $R {a}^{86}$
Actinium $A {c}^{89}$
Uranium ${U}^{92}$

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