86Rn[222]
Radon (Rn)
Element 86 · Noble gas
Radon (Rn) is a chemical element with atomic number 86. It is classified as a noble gas in period 6, group 18 of the periodic table (the p-block). Its most stable known isotope has mass number 222 and its ground-state electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶.
Radon facts
| Atomic number (Z) | 86 |
|---|---|
| Symbol | Rn |
| Mass number of most stable isotope | [222] |
| Category | Noble gas |
| Group | 18 |
| Period | 6 |
| Block | p-block |
| Electron configuration | [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶ |
| Electronegativity (Pauling) | 2.2 |
| State at 20 °C | Gas |
| Protons / electrons | 86 / 86 |
| Neutrons (most common isotope, approx.) | 136 |
| Molar mass | 222 g/mol |