Periodex

General properties

Group

n/a

Period

period 7

Category

actinoids

Standard atomic weight

-

Melting point

1259 K (beta)

Boiling point

2900 K (beta)

Phase at STP

solid

Additional properties

Block

f-block

Electron configuration

[Rn] 5f⁹ 7s²

Electrons per shell

2, 8, 18, 32, 27, 8, 2

Electronegativity

1.3

Density

alpha: 14.78 g/cm³ beta: 13.25 g/cm³

Oxidation states

+2, +3, +4, +5

CAS Number

7440-40-6

Natural isotopes

Discovery history

Discovered by

Lawrence Berkeley National Laboratory

Year of discovery

1949

Origin of name

Berkeley, California, USA, where the element was first synthesized