californium (Cf)

Californium (Cf) is a radioactive, metallic element of the actinide series, and also a transuranic element, first made in 1950 at the University of California at Berkeley by alpha particle bombardment of the curium isotope 242Cu. Californium presents biological dangers because one microgram releases 170 million neutrons a minute. Of numerous isotopes that have been synthesized, the most stable isotope is 244Cf (half-life 800 yr). Atomic number 98.