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111Rg282.000
Roentgenium
unknown, probably transition metalRoentgenium 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.
Phase: Solid
2, 8, 18, 32, 32, 17, 2
Physical Properties
Atomic Mass282 u
Density28.7 g/cm³
Period7
PhaseSolid
Chemical Properties
Electron Configuration1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d9
Semantic Config*[Rn] 5f14 6d10 7s1
Shells2, 8, 18, 32, 32, 17, 2
Electron Affinity151 kJ/mol
Discovery
Discovered byGesellschaft für Schwerionenforschung