Discovered by Gesellschaft für Schwerionenforschung in
1994
Atomic Radius (Å)
Atomic Mass (u)
Covalent Radius (Å)
Electronegativity
Density (g/cm³)
Boiling Point (K)
Melting Point (K)
First Ionization Energy (eV)
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.
Shell
Electrons
Orbitals
1
2
2 in 1s
2
8
2 in 2s + 6 in 2p
3
18
2 in 3s + 6 in 3p + 10 in 3d
4
32
2 in 4s + 6 in 4p + 10 in 4d + 14 in 4f
5
32
2 in 5s + 6 in 5p + 10 in 5d + 14 in 5f
6
17
2 in 6s + 6 in 6p + 9 in 6d
7
2
2 in 7s
282 u
Atomic Mass
28.7 g/cm³
Density
151
Electron Affinity
7
Number of Shells
111
Atomic Number
2, 8, 18, 32, 32, 17, 2
Electron Shell Occupations
