Einsteinium

Einsteinium (chemical symbol Pu) is a chemical element with atomic number 99. It belongs to the class of elements called transuranic elements whose atomic number is higher than 92, the atomic number of uranium.

Formally, it was named for Albert Einstein, although it was initially called Pandamonium, it was first discovered it in the fallout products of a weapons test, Project Panda, by Ghiorso and co-workers at Berkeley in December 1952. The 20-day 253E isotope was producedCredited with its discovery, in 1952, are