Periodex

General properties

Group

n/a

Period

period 6

Category

lanthanoids

Standard atomic weight

-

Melting point

1315 K (1042 °C)

Boiling point

3273 K (3000 °C)

Phase at STP

solid

Additional properties

Block

f-block

Electron configuration

[Xe] 4f⁵ 6s²

Electrons per shell

2, 8, 18, 23, 8, 2

Electronegativity

1.13

Density

7.26 g/cm³

Oxidation states

+2, +3

CAS Number

7440-12-2

Natural isotopes

Discovery history

Discovered by

Chien Shiung Wu, Emilio Segrè e Hans Bethe

Year of discovery

1942

Origin of name

Prometheus of Greek mythology who stole fire from the Gods and gave it to humans