Rg
Roentgenium
Roentgenium is a chemical element with the symbol Rg and atomic number 111. It has a mass number of 282, sits in period 7 and group 11, and is classified as a transition metal.
Properties
| Symbol | Rg |
|---|---|
| Atomic number | 111 |
| Mass number | 282 |
| Category | Transition metal |
| Group | 11 |
| Period | 7 |
| Electron configuration | [Rn] 5f14 6d9 7s2 |
| Outer-shell electrons | 2 |
The figure of 282 is a mass number rather than a measured atomic weight, because this element has no stable isotope.
Calculate with roentgenium
- Molar mass of any formula containing it
- Electron configuration, including ions
- Effective nuclear charge by Slater's rules
- Average atomic mass from isotope abundances
Group 11
Atomic weights are the IUPAC 2021 standard values, abridged to the conventional five significant figures. Group, period, category and electron configuration are derived from the atomic number rather than stored, so they cannot drift out of step with it.