Periodex

General properties

Group

n/a

Period

period 7

Category

actinoids

Standard atomic weight

-

Melting point

1449 K (1176 °C)

Boiling point

2880 K (2607 °C)

Phase at STP

solid

Additional properties

Block

f-block

Electron configuration

[Rn] 5f⁷ 7s²

Electrons per shell

2, 8, 18, 32, 25, 8, 2

Electronegativity

1.13

Density

12 g/cm³

Oxidation states

+2, +3, +4, +5, +6, +7 (an amphoteric oxide)

CAS Number

7440-35-9

Natural isotopes

Discovery history

Discovered by

Glenn T. Seaborg, Ralph A. James, Leon O. Morgan, and Albert Ghiorso

Year of discovery

1944

Origin of name

Americas, the continent where the element was first synthesized