111
Rg
282
Roentgenium (Rg)
Element 111 · Period 7 · Group 11
unknown
solid at room temp
d-block
radioactive
synthetic
About Roentgenium
Named after Röntgen. Predicted to be a liquid metal. Only microsecond half-life.
Physical Properties
Atomic Mass
282 u
State at 25°C
Solid
Density
28.7 g/cm³
Magnetism
Unknown
Atomic Properties
Electron Configuration
[Rn] 5f¹⁴ 6d¹⁰ 7s¹
Electron Shells
2, 8, 18, 32, 32, 18, 1
Oxidation States
+3
Discovery & History
Discovered By
Peter Armbruster
Discovery Year
1994
Named By
IUPAC
Name origin: Wilhelm Röntgen (X-ray discoverer)
Frequently Asked Questions
- Is Roentgenium a metal, nonmetal, or metalloid?
- Roentgenium is classified as a unknown.
- What state is Roentgenium in at room temperature?
- Roentgenium is a solid at standard room temperature (25°C).
- What is the atomic mass of Roentgenium?
- Roentgenium has an atomic mass of 282 atomic mass units (u).
- Who discovered Roentgenium?
- Roentgenium was discovered by Peter Armbruster in 1994.
- Where is Roentgenium on the periodic table?
- Roentgenium is element number 111, located in period 7 and group 11.