Assertion: potassium | /r/HasProperty | 0.012%
Facets:
Source sentences:
text: Potassium ( 19 K) has 25 known isotopes from 33K to 57K, plus an unconfirmed report of 59K. Three of those isotopes occur naturally: the two stable forms 39K (93.3%) and 41K (6.7%), and a very long-lived radioisotope 40K (0.012%).