Radon (Rn)
Radon is the chemical element with atomic number 86 and symbol Rn. It is a noble gas in period 6, group 18, with a standard atomic weight of 222 u.
Key facts
- Z
- 86
- Atomic weight
- 222 u no stable isotope
- Category
- noble gas
- State at 298 K
- Gas
- Occurrence
- from decay, radioactive
- Discovered
- 1899
- CAS
- 10043-92-2
Measured properties
| Property | Value | Source |
|---|---|---|
| Melting point | 202 K | National Center for Biotechnology Information (NIH) |
| Boiling point | 211.45 K | National Center for Biotechnology Information (NIH) |
| Density stp | 0.01 g/cm³ | National Center for Biotechnology Information (NIH) |
| Atomic radius empirical | 220 pm | National Center for Biotechnology Information (NIH) |
| Ionization energy 1st | 1,036.7 kJ/mol | National Center for Biotechnology Information (NIH) |
Electron configuration
- Noble gas notation
- [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶
- Full notation
- 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁶
- Electrons per shell
- 2, 8, 18, 32, 18, 8