Element 86 · Noble gas
Radon (Rn) — Element 86
From radium
Radon (Rn) is a noble gas in Period 6, Group 18 of the periodic table with atomic number 86, standard atomic weight [222] u, and ground-state electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶. At standard temperature and pressure it is classified as a gas with 0 valence electrons and common oxidation states 0.
Historical radiotherapy; now a hazard
What are the atomic properties and physical constants of Radon?
Reference constants compiled from IUPAC standard atomic weights, the NIST Atomic Spectra Database, and the CRC Handbook.
- Atomic number (Z)
- 86
- Standard atomic mass
- [222] u
- Chemical family
- Noble gas
- Ground-state configuration
- [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶
- Electrons per shell
- 2, 8, 18, 32, 18, 8
- Valence electrons
- 0
- Common ion charges / oxidation states
- 0
- Phase at STP
- Gas
- Pauling electronegativity
- —
- First ionization energy
- 1,037 kJ/mol
- Atomic radius
- 120 pm
- Melting point
- -71 °C
- Boiling point
- -62 °C
- Discovery year
- 1900
- Table coordinate
- Period 6, Group 18
- Radioactivity
- Radioactive (no stable isotopes)
How are electrons arranged across Radon’s shells?
A neutral Radon atom contains 86 electrons distributed across 6 occupied principal energy shells ([Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶). The table below compares Radon’s shell occupancy against each shell’s theoretical 2n² capacity.
| Principal Shell (n) | Spectroscopic Letter | Electrons in Rn | Max Shell Capacity (2n²) |
|---|---|---|---|
| n = 1 | K | 2 e⁻ | 2 e⁻ |
| n = 2 | L | 8 e⁻ | 8 e⁻ |
| n = 3 | M | 18 e⁻ | 18 e⁻ |
| n = 4 | N | 32 e⁻ | 32 e⁻ |
| n = 5 | O | 18 e⁻ | 50 e⁻ |
| n = 6 | P | 8 e⁻ | 72 e⁻ |
Frequently Asked Questions about Radon (Rn)
What is the atomic mass and atomic number of Radon (Rn)?
Radon (Rn) has atomic number Z = 86 (86 protons in its nucleus) and an IUPAC standard atomic weight of [222] u. It sits in Period 6, Group 18 and is classified as a noble gas.
What is the ground-state electron configuration of Radon?
The neutral ground-state electron configuration of Radon (Z = 86) is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶. Across its 6 occupied principal shells (n = 1 to n = 6), the electrons per shell are 2, 8, 18, 32, 18, 8, with 0 valence electrons participating in bonding.
What are the common ion charges and electronegativity of Radon?
Radon commonly forms 0 oxidation states or ion charges in compounds. Its Pauling electronegativity is — and its first ionization energy is 1,037 kJ/mol.
When was Radon discovered and what is it used for?
Radon was discovered in 1900 (From radium). Historical radiotherapy; now a hazard
How does Radon compare to neighboring elements?
Other noble gas elements: