einsteinium

Name einsteinium
Symbol Es
Atomic Weight 252.08
Atomic Number 99
CAS ID 7429-92-7
Group Number (none)
Group Name Actinoid
Period Number 7
Origin of Name Named after Albert Einstein.
Year Discovered 1952
Discovery Credits Discovered in the debris of the 1952 thermonuclear explosion in the Pacific by G. R. Choppin, S. G. Thompson, A. Ghlorso, and B. G. Harvey.
Class Metallic
Color Unknown, but probably metallic and silvery white or gray in appearance.
Standard State Solid at 77 F & 298 K
Description Radioactive, silvery metal which does not occur naturally. attacked by oxygen, steam, and acids, but not alkalis.

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