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 | |||||||||||
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Symbol | Rg | ||||||||||
Atomic number | 111 | ||||||||||
Group | 11 | ||||||||||
Period | 7 | ||||||||||
Block | d | ||||||||||
Element category | Unknown | ||||||||||
Physical properties | |||||||||||
Phase at STP | Solid | ||||||||||
Density | 28.7 g/cm3 | ||||||||||
Atomic weight | 282 u | ||||||||||
Melting point | - | ||||||||||
Boiling point | K °C °F | ||||||||||
Atomic properties | |||||||||||
Electronegativity (Pauling Scale) | |||||||||||
Electron affinity | 151 kJ/mol | ||||||||||
Oxidation states | (−1), (+1), (+3), (+5), (+7) (predicted) | ||||||||||
Ionization energies |
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Electron configuration | |||||||||||
Elektronkonfiguration (shorthand) | [Rn] 5f14 6d9 7s2 | ||||||||||
Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d9 7s2 | ||||||||||
Electrons per shell | 2, 8, 18, 32, 32, 17, 2 | ||||||||||
History | |||||||||||
Discovered | 1994 | ||||||||||
Discovered by | Gesellschaft für Schwerionenforschung |