Assertion: beryllium's isotope | /r/HasProperty | stable
Facets:
Source sentences:
text: Beryllium has only one stable isotope, Be-9.
text: The other 10 isotopes of beryllium are also unstable, and also radioactive, and they have very short half-lives, the longest of which is 53 days, beryllium-7.
text: The only naturally occurring isotope is the stable beryllium-9, although 11 other synthetic isotopes are known.