Radon (Rn)
Radon (Rn) is element 86 of the periodic table, a noble gas in period 6 and group 18. It has no stable isotope and no standard atomic weight; 222 is the mass number of its longest-lived isotope. At room temperature it is a gas; it melts at -71.15 °C and boils at -61.7 °C.
| Atomic number | 86 |
|---|---|
| Symbol | Rn |
| Standard atomic weight | [222] (mass number of the longest-lived isotope) |
| Molar mass | [222] g/mol |
| Category | Noble gas |
| Group | 18 |
| Period | 6 |
| Block | p-block |
| Electron configuration | [Xe] 6s2 4f14 5d10 6p6 |
| Oxidation states | 0 |
| Electronegativity (Pauling) | — |
| Atomic radius (van der Waals) | 220 pm |
| First ionisation energy | 10.745 eV (1036.7 kJ/mol) |
| Electron affinity | — |
| State at room temperature | Gas |
| Melting point | 202 K (-71.15 °C) |
| Boiling point | 211.45 K (-61.7 °C) |
| Density | 9.73 g/L |
| Discovered | 1900 |
Group 18
Calculate with Radon
Atomic weight: IUPAC CIAAW — no standard atomic weight; mass number in brackets. Other properties: PubChem (U.S. National Library of Medicine, public domain). Values such as melting point and radius depend on how they were measured; check a data book for precise work.