Assertion: fermium's isotope | /r/HasProperty | discovered
Facets:
Source sentences:
text: The first isotope to be discovered was 255Fm in 1952.
text: Radioactive isotopes of mass number 244–259 have been discovered.
text: Francium-223 is the most stable isotope, with a half-life of 21.8 minutes, and it is highly unlikely that an isotope of francium with a longer half-life will ever be discovered or synthesized.
text: Additionally, 34 radioactive isotopes have been discovered.