| 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 | |||
|---|---|---|---|
| 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 | K °C °F | ||
| Boiling point | K °C °F | ||
Atomära egenskaper | |||
| Electronegativity (Pauling Scale) | |||
| Electron affinity | 151 kJ/mol | ||
| Ionization energies |
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Electron configuration | |||
| 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 | ||