Roentgenium (Rg)
Unknown properties · Radioactive · Synthetic
Roentgenium honours Wilhelm Röntgen, discoverer of X-rays. Predicted to be a noble, silvery relative of gold, it decays far too quickly for anyone to check.
Position on the periodic table
Atomic properties
| Atomic number | 111 |
|---|---|
| Atomic mass | 282 amu |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d9 |
| Noble gas shorthand | *[Rn] 5f14 6d10 7s1 |
| Electrons per shell | 2, 8, 18, 32, 32, 17, 2 |
| Valence electrons (outer shell) | 2 |
| Common oxidation states | None common |
| Electronegativity (Pauling) | Not available |
| Covalent radius (approx.) | Not available |
| First ionization energy | Not available |
| Electron affinity | 151 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | 28.7 g/cm³ |
| Melting point | Not available |
| Boiling point | Not available |
| Appearance | Not available |
| Radioactive | Yes |
| Origin | Synthetic (lab-made) |
Electron configuration of roentgenium
Roentgenium's ground-state electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d9, usually shortened to *[Rn] 5f14 6d10 7s1. Its electrons occupy 7 shells (2, 8, 18, 32, 32, 17, 2), placing it in period 7 of the d-block. Explore it interactively in the electron configuration calculator.
Uses of roentgenium
- Fundamental research only
Biological role: None.
Occurrence: Entirely synthetic.
History and discovery
Discovered: 1994 — Gesellschaft für Schwerionenforschung. Name origin: Named after Wilhelm Conrad Röntgen.
Created at GSI Darmstadt in December 1994, weeks after darmstadtium.
Safety notes
Radioactive; exists for milliseconds.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Roentgenium
1. What is the chemical symbol of Roentgenium?
2. What is the atomic number of Roentgenium?
3. Which category does Roentgenium belong to?
4. What is the state of Roentgenium at room temperature?
5. Which period of the periodic table is Roentgenium in?
Roentgenium FAQs
What is the atomic number of roentgenium?
Roentgenium's atomic number is 111 — every roentgenium atom has 111 protons in its nucleus.
What is the symbol for roentgenium?
Rg. Named after Wilhelm Conrad Röntgen.
Is roentgenium a metal, nonmetal, or metalloid?
Roentgenium is classified as a unknown properties.
What state is roentgenium at room temperature?
At about 25 °C, roentgenium is a solid.
What is roentgenium used for?
Key uses include: fundamental research only.
Related elements
Keep working with this element
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