Rg
Roentgenium
Element 111 · Transition metal
Roentgenium (Rg)
Roentgenium is a synthetic element predicted to be a heavier relative of gold.
- Transition metal
- Period 7
- Group 11
- d-block
- solid at room temperature
- ☢ Radioactive
Key properties
- Atomic mass
- [282]
- u
- Electron configuration
- [Rn] 5f14 6d10 7s1
- Melting point
- —
- Boiling point
- —
- Density
- 28.7 g/cm³
- Electronegativity
- —
- Atomic radius
- —
- 1st ionisation energy
- —
Superheavy elements have only been made a few atoms at a time. Most properties shown are theoretical predictions.
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about roentgenium
- 01
It was first made a month after darmstadtium, at the same lab.
- 02
Relativistic effects may make it behave quite differently from gold.
- 03
Its name was approved in 2004, on the 109th anniversary of the discovery of X-rays.
Applications
What is roentgenium used for?
- Research
History
Discovery & name origin
Discovered by
Year
Where
Germany
Name origin
From Wilhelm Röntgen, discoverer of X-rays.
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 111
- Atomic mass
- [282] u
- Group
- 11
- Period
- 7
- Block
- d-block
- Electron configuration
- [Rn] 5f14 6d10 7s1
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d9
- Electrons per shell
- 2, 8, 18, 32, 32, 17, 2
- Electronegativity (Pauling)
- —
- Electron affinity
- —
- Atomic radius (van der Waals)
- —
- Stable isotopes
- None — all isotopes are radioactive
Oxidation states
Highlighted: common oxidation states (+5, +3, +1, -1).
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Solid (predicted)
- Melting point
- —
- Boiling point
- —
- Density
- 28.7 g/cm³
- Molar heat capacity
- —
- Appearance
- —
- CPK model colour
- —
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Roentgenium questions
What is Rg on the periodic table?
Rg is the symbol for roentgenium, element 111 on the periodic table. It sits in group 11, period 7, in the transition metal category, and has an atomic mass of [282].
What is the atomic number of roentgenium?
Roentgenium has atomic number 111, so every roentgenium atom has 111 protons in its nucleus. Its symbol is Rg and its atomic mass is [282].
Who discovered roentgenium?
Roentgenium was discovered by Sigurd Hofmann, Peter Armbruster and Gottfried Münzenberg in 1994 (Germany). The name comes from from Wilhelm Röntgen, discoverer of X-rays.
What is roentgenium used for?
Roentgenium is used for: research.
Is roentgenium a metal?
Yes. Roentgenium is a transition metal, one of the metallic elements.
What is the electron configuration of roentgenium?
The electron configuration of roentgenium is [Rn] 5f14 6d10 7s1 (predicted). Its 111 electrons are arranged in shells as 2, 8, 18, 32, 32, 17, 2.