86222RnRadon
Radon (Rn) — element 86noble gas · group 18, period 6
Radon is a chemical element with the symbol Rn and atomic number 86. It is a noble gas in group 18, period 6 of the periodic table (the p-block), with a standard atomic mass of 222 u. At room temperature (25 °C) radon is a gas.
💡 Known for: A radioactive gas that seeps out of the ground; it is a leading cause of lung cancer after smoking.
# Radon properties
| Symbol | Rn |
|---|---|
| Atomic number | 86 |
| Atomic mass | 222 u |
| Category | noble gas |
| Group | 18 |
| Period | 6 |
| Block | p-block |
| Electron configuration | [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶ |
| Full configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁶ |
| Electrons per shell | 2, 8, 18, 32, 18, 8 |
| Protons / electrons | 86 / 86 |
| State at 25 °C | gas |
| Melting point | 202 K (-71.1 °C, -96.1 °F) |
| Boiling point | 211.3 K (-61.8 °C, -79.3 °F) |
| Density | 9.73 g/L |
| Electronegativity (Pauling) | 2.2 |
| First ionization energy | 10.749 eV |
| Atomic radius | 120 pm |
| Discovered | 1900 |
# Electron configuration of radon
The electron configuration of radon is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶, written out in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁶. Its 86 electrons fill 6 shells as 2, 8, 18, 32, 18, 8, so the outermost shell holds 8 electrons. As a group 18 element, radon has 8 valence electrons.
# Related elements
AtAstatineprevious elementFrFranciumnext elementHeHeliumgroup 18NeNeongroup 18ArArgongroup 18KrKryptongroup 18XeXenongroup 18OgOganessongroup 18
# Radon FAQ
What is the atomic number of radon?
The atomic number of radon is 86: every radon atom has 86 protons in its nucleus. Its symbol is Rn.
What is the atomic mass of radon?
The standard atomic mass of radon is 222 u.
What is the electron configuration of radon?
Radon's electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶ (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁶), with 2, 8, 18, 32, 18, 8 electrons per shell.
Is radon a metal?
No. Radon is a noble gas, a nonmetal.
What is the melting point of radon?
Radon melts at 202 K (-71.1 °C, -96.1 °F) and boils at 211.3 K (-61.8 °C, -79.3 °F).
What is radon used for / known for?
A radioactive gas that seeps out of the ground; it is a leading cause of lung cancer after smoking.