Element: Roentgenium
This element has only been produced a few atoms at a time, so most of its properties have never been measured - missing values are omitted.
General data
| Element name | Roentgenium |
|---|---|
| Chemical symbol | Rg |
| Atomic number Z | 111 |
| Year discovered | 1994 |
| Standard state (25°C) | Expected to be a solid |
| Category | Transition metal |
| Block | d |
| Atomic mass | [282] |
Physical properties
none - only single atoms have been produced
Energy properties
none - only single atoms have been produced
Atomic structure
| Protons | 111 (Atomic number) |
|---|---|
| Neutrons (Rg-282, longest-lived isotope) | 171 |
| Electrons | 111 |
| Electron configuration | [Rn] 7s² 5f¹⁴ 6d⁹ (predicted) |
| Oxidation states | +5, +3, +1, -1 |
Ionization energies - NIST ASD (0 states)
none - only single atoms have been produced
Data sources
- PubChem Periodic Table API - Retrieved on 29 June 2026 - licence: CC0
- IUPAC CIAAW - Abridged Standard Atomic Weights 2024 - Table version: 2024 - licence: Public domain
- NNDC Wallet Cards 2023 - Data as of 15 October 2024 - licence: Public domain
- NIST Atomic Spectra Database (ASD) - Retrieved on 29 June 2026 - licence: © U.S. Secretary of Commerce