Rn
Radon
Element 86 · 222.01758 u
Radon is a radioactive noble gas and the second leading cause of lung cancer after smoking.
Physical Properties
| Atomic Mass | 222.01758 u |
| Density | 0.00973 g/cm³ |
| Melting Point | 202.0 K |
| Boiling Point | 211.3 K |
| Appearance | Colorless gas |
| State at Room Temp | Gas |
Chemical Properties
| Electronegativity | 2.2 (Pauling) |
| 1st Ionization Energy | 1037.0 kJ/mol |
| Electron Affinity | -68.0 kJ/mol |
| Oxidation States | +2, +6 |
Atomic Properties
| Electron Configuration | [Xe] 4f14 5d10 6s2 6p6 |
| Atomic Radius | 150.0 pm |
| Covalent Radius | 150.0 pm |
| Van der Waals Radius | 220.0 pm |
Discovery
| Discovered By | Friedrich Ernst Dorn |
| Discovery Year | 1900 |
| Location | Halle, Germany |
| Named After | Named after radium, from which it is produced |
About Radon
Radon is a colorless, odorless radioactive gas formed from radium decay. It is the densest gas known. Radon seeps from the ground and accumulates in basements, causing thousands of lung cancer deaths per year.
Uses & Applications
Radon testing in buildings, earthquake prediction research, and hydrological research.
Fun Fact
Radon is the second leading cause of lung cancer after smoking, yet it is odorless and invisible. The EPA recommends testing all homes.
Isotopes
| Mass Number | Abundance | Half-Life | Stable |
| 211 | - | 14.6 hours | No |
| 220 | - | 55.6 seconds | No |
| 222 | - | 3.8235 days | No |
Electron Configuration
[Xe] 4f14 5d10 6s2 6p6