111Rg282.000
Transition Metald-blockRadioactivePredicted properties
Roentgenium
Element 111 on the periodic table, symbol Rg, group 11, period 7.
Roentgenium 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.
Properties
- Atomic Number
- 111
- Atomic Mass
- 282.0000 u
- Group
- 11
- Period
- 7
- Block
- d-block
- Category
- Transition Metal
- State at 25 °C
- Solid
- Melting Point
- Not measured
- Boiling Point
- Not measured
- Density
- 28.7 g/cm³
- Atomic Radius
- Not measured
- Electronegativity
- Not measured
- Oxidation States
- None commonly seen
- Abundance in Crust
- Vanishingly rare
- Discovered
- 1994
- Discovered By
- Gesellschaft für Schwerionenforschung
Electron Configuration
*[Rn] 5f14 6d10 7s1
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d9
Elements near Roentgenium
Elements in the same group share the number of outer electrons and behave in similar ways. Elements in the same period share a shell, so they change steadily from left to right.