Rn
Radon
Radon is a chemical element with the symbol Rn and atomic number 86. It has a mass number of 222, sits in period 6 and group 18, and is classified as a noble gas.
Properties
| Symbol | Rn |
|---|---|
| Atomic number | 86 |
| Mass number | 222 |
| Category | Noble gas |
| Group | 18 |
| Period | 6 |
| Electron configuration | [Xe] 4f14 5d10 6s2 6p6 |
| Outer-shell electrons | 8 |
The figure of 222 is a mass number rather than a measured atomic weight, because this element has no stable isotope.
Calculate with radon
- 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 18
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.