Darmstadtium Copernicium

Roentgenium (Rg)

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

Atomic number

111

Group

Period

Block

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

1	1022.7 kJ/mol
2	2074.4 kJ/mol
3	3077.9 kJ/mol
4	4052.4 kJ/mol
5	5306.7 kJ/mol

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