> A chemical element is called "radioactive" whenever at least one of its naturally occurring isotopes is radioactive. I think you the defintion is the opposit

> A chemical element is called "radioactive" whenever at least one of its naturally occurring isotopes is radioactive. I think you the defintion is the opposite, ie that an element is considered radioactive if NO isotopes are stable (ie ALL are radioactive). https://www.thoughtco.com/list-of-radioactive-elements-608644 https://www.thoughtco.com/list-of-radioactive-elements-60864...