Radon (Rn): Electron Configuration, Properties and Uses
Radon (Rn): Electron Configuration, Properties and Uses
Electron configuration [Xe] 6s2 4f14 5d10 6p6 · group 18 · period 6 · Ar [222]
Radon data
- Atomic number
- 86
- Relative atomic mass
- [222]
- Group
- 18
- Period
- 6
- Block
- p
- Category
- Noble gas
- Electron configuration
- [Xe] 6s2 4f14 5d10 6p6
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6
- Electrons per shell
- 2, 8, 18, 32, 18, 8 (K L M N O P)
- Valence electrons
- 8
- Electronegativity (Pauling)
- no data
- First ionisation energy
- 10.745 eV
- Atomic radius (van der Waals)
- 220 pm
- State at room temperature
- Gas
- Melting point
- −71.1 °C
- Boiling point
- −61.7 °C
- Density
- 9.73 g/L (0 °C, 1 atm)
- Common oxidation states
- 0
- Discovered
- 1900
Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.
Electron shell diagram
K 2 · L 8 · M 18 · N 32 · O 18 · P 8
Orbital diagram (outer electrons)
About radon
Radon, symbol Rn, is element number 86 in the periodic table. It is a noble gas in group 18, period 6, p-block. Radon was first discovered in 1900. At room temperature radon is a gas that is heavier than air (9.73 g/L) and liquefies at −61.7 °C.
Radon electron configuration
The electron configuration of radon is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6, or in short [Xe] 6s2 4f14 5d10 6p6. Its electrons occupy 6 shells: K = 2, L = 8, M = 18, N = 32, O = 18, P = 8. Radon has 8 valence electrons in the P shell (6s2 6p6), which is why it sits in group 18.
Filling order: 1s2(2) → 2s2(4) → 2p6(10) → 3s2(12) → 3p6(18) → 4s2(20) → 3d10(30) → 4p6(36) → 5s2(38) → 4d10(48) → 5p6(54) → 6s2(56) → 4f14(70) → 5d10(80) → 6p6(86)
Uses of radon
Well-known applications of radon include indoor air monitoring and geological research; natural radon seeping from the ground is a leading cause of lung cancer after smoking.
Safety
Radon is radioactive. Using, storing or transporting radioactive material requires a licence from the national regulator (BAPETEN in Indonesia). Always read the safety data sheet (SDS) before working with a chemical.
Other elements in group 18
Frequently asked questions
What is the electron configuration of radon?
The electron configuration of radon (Rn, atomic number 86) is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6, or [Xe] 6s2 4f14 5d10 6p6 in short. By shell: 2, 8, 18, 32, 18, 8.
How many valence electrons does radon have?
Radon has 8 valence electrons.
Which group and period is radon in?
Radon is in group 18, period 6, p-block.
What is the atomic mass of radon?
Radon has no stable isotope, so the mass number of its longest-lived isotope, [222], is given.
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