Roentgenium

Chaitra 05/07/2026 12:03:03 Updated 05/07/2026 12:03:03

Property	Value
Atomic Number	111
Element	Roentgenium
Symbol	Rg
Atomic Mass	[282] (most stable isotope)
Number of Neutrons	171 (Roentgenium-282)
Number of Protons	111
Number of Electrons	111
Period	7
Group	11
Phase	Solid (predicted)
Radioactive	Yes
Natural	No (synthetic element)
Metal	Yes (predicted)
Nonmetal	No
Metalloid	No
Type	Transition Metal
Atomic Radius	— (not well established)
Electronegativity	— (not well established)
First Ionization Energy	~7.6 eV (estimated)
Density	~28.7 g/cm³ (estimated)
Melting Point	— (not well established)
Boiling Point	— (not well established)
Number of Isotopes	No stable isotopes (Rg-282 most notable)
Discoverer	Gesellschaft für Schwerionenforschung (GSI), Germany
Year	1994
Specific Heat	— (not well established)
Number of Shells	7
Number of Valence Electrons	11