Californium

Actinide · atomic number 98

98251CfCaliforniumSolidActinide

Californium is a radioactive metallic chemical element with symbol Cf and atomic number 98. The element was first made in 1950 at the University of California Radiation Laboratory in Berkeley, by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium).

Properties of Californium

Element category	Actinide
Atomic number	98
Atomic mass	251 u
Phase at STP	Solid
Group	3
Period	7
Block	f
Electron configuration	[Rn] 5f10 7s2
Electrons per shell	2, 8, 18, 32, 28, 8, 2
Electronegativity (Pauling)	1.3
Melting point	1173 K (900 °C)
Boiling point	1743 K (1470 °C)
Density	15.1 g/cm3
Discovered by	Lawrence Berkeley National Laboratory

← Berkelium · Periodic table · Einsteinium → Es

About the actinide group

Mostly radioactive, heavy metals — several made only in reactors — whose fission powers nuclear energy and weapons.

Data: Periodic-Table-JSON (CC BY-SA 3.0) · stored statically on our server. https://en.wikipedia.org/wiki/Californium

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