Plutonium (Pu)

From Wikipedia, the free encyclopediaPlutonium is a transuranic radioactive chemical element with symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation states.

Plutonium in the periodic table

SymbolPu
Atomic number94
Group0
Period7
Blockf
Element categoryActinide

Physical properties

Phase at STPSolid
Density19.816 g/cm3
Atomic weight244 u
Melting point912.5 K
639.35 °C
1182.83 °F
Boiling point3505 K
3231.85 °C
5849.33 °F

Atomära egenskaper

Electronegativity (Pauling Scale)1.28
Electron affinity-48.33 kJ/mol
Ionization energies
1584.7 kJ/mol

Electron configuration

Electron configuration1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f6 6s2 6p6 7s2
Electrons per shell2, 8, 18, 32, 24, 8, 2

History

Discovered1940
Discovered byGlenn T. Seaborg
Arthur Wahl
Joseph W. Kennedy
Edwin McMillan