Roentgenium (Rg)

From Wikipedia, the free encyclopediaRoentgenium is a chemical element with symbol Rg and atomic number 111. It is an extremely radioactive synthetic element (an element that can be created in a laboratory but is not found in nature); the most stable known isotope, roentgenium-282, has a half-life of 2.1 minutes. Roentgenium was first created in 1994 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany.

Roentgenium in the periodic table

SymbolRg
Atomic number111
Group11
Period7
Blockd
Element categoryUnknown

Physical properties

Phase at STPSolid
Density28.7 g/cm3
Atomic weight282 u
Melting point K
°C
°F
Boiling point K
°C
°F

Atomära egenskaper

Electronegativity (Pauling Scale)
Electron affinity151 kJ/mol
Ionization energies
1 kJ/mol

Electron configuration

Electron configuration1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d9 7s2
Electrons per shell2, 8, 18, 32, 32, 17, 2

History

Discovered1994
Discovered byGesellschaft für Schwerionenforschung