Assertion: tellurium's isotope | /r/HasProperty | radioactive
Facets:
Source sentences:
text: Tellurium has radioactive isotopes and is the lightest element to exhibit alpha decay.
text: 127I is stable, the only one of the isotopes of iodine that is nonradioactive.
text: Sulfur has four stable isotopes, 20 radioactive ones, and one isomer.