Radon Oxidation States

Radon (Rn) has one common oxidation state: 0. Its filled 6p⁶ valence shell makes it nearly inert, though +2 has been observed in rare fluorine compounds such as RnF₂.

86 Rn (222)

Radon

Noble Gas — Period 6, Group 18

Symbol: Rn
Atomic no.: 86
Atomic mass: (222) u
Block: p-block
Phase: Gas
Discovered: 1900

Electron Configuration

[Xe]
e
e
e
e
e
e
e
e
e
e
e
e
e
e
+40
Xenon core (54 electrons)
4f
e
e
e
e
e
e
e
e
e
e
e
e
e
e
Inner — lanthanide f-block
5d
e
e
e
e
e
e
e
e
e
e
Inner — d-block filled
6s
e
e
Valence — filled
6p
e
e
e
e
e
e
Valence — filled (octet complete)
Notation
Full: [Xe] 4f14 5d10 6s2 6p6
Noble gas: [Rn] = [Xe] 4f14 5d10 6s2 6p6

All 86 electrons fill through the 6p subshell, closing radon's valence shell. The large atomic radius and relativistic orbital expansion lower the ionization energy but do not open room-temperature chemistry.

Key Properties

Ionization energy (1st) 10.748 eV
Ionization energy (2nd) 21.4 eV (est.)
Electronegativity None (Pauling)
Boiling point −61.7 °C (211.5 K)
Melting point −71.0 °C (202.2 K)
Density 9.73 g/L (STP)
Most stable isotope Rn-222 (t½ = 3.82 days)
Known compounds RnF₂ (experimentally observed)

Oxidation States of Radon

Click a row to see details.

State Occurrence Example
0 Always (standard conditions) Rn (elemental gas)
+2 Rare — fluorine compounds only RnF₂

Noble Gas Oxidation State Comparison

Reactivity increases down Group 18 as ionization energy falls. Radon's +2 state is theoretically expected and experimentally indicated, but radioactivity prevents thorough characterization.

Why Radon Is Nearly Inert (Despite Its Low IE)

    Radon's Main Compound: RnF₂

    Name
    Radon Difluoride
    Formula
    RnF₂
    Rn Oxidation State
    +2
    Context
    RnF₂ has been observed experimentally through tracer methods using Rn-222, analogous to the well-characterized XeF₂ and KrF₂. Its short-lived radioactive nature prevents bulk synthesis or single-crystal X-ray determination. Radon's ionization energy (10.75 eV) is lower than krypton's (14.00 eV), so fluorine chemistry is thermodynamically more favorable, but radiation damage destroys the compound before detailed study is possible. Higher fluorides (RnF₄, RnF₆) are theoretically plausible but not yet experimentally confirmed.

    Summary

    Radon (Rn) has one common oxidation state: 0. Its filled 6p⁶ valence shell makes it nearly inert, though +2 has been observed in rare fluorine compounds such as RnF₂.

    How it works

    1. Review the element card on the left and click "Copy Element Data" to get a plain-text reference card.
    2. The electron configuration panel shows the filled 6s and 6p orbitals responsible for radon's chemical inertness.
    3. Click a row in the oxidation states table to see a detailed explanation of that state.
    4. The noble gas comparison chart places radon alongside all six Group 18 elements to show the reactivity trend down the group.
    5. The inertness explainer lists the chemical reasons radon rarely reacts despite its relatively low ionization energy.
    6. Key properties — ionization energies, boiling point, density, half-life, and known compounds — appear in the properties panel.

    Use cases

    • Looking up radon's oxidation state for chemistry homework or an exam.
    • Teaching how noble gas reactivity increases down Group 18 using radon as the heaviest example.
    • Comparing radon to lighter noble gases like xenon and krypton that also form fluorine compounds.
    • Understanding why radon's radioactivity makes its chemistry difficult to study experimentally.
    • Studying Period 6 elements and the role of relativistic effects on chemical reactivity.
    • Background reading before working on noble gas chemistry, radiochemistry, or nuclear physics.

    Frequently Asked Questions

    Last updated: 2026-07-24 · Reviewed by Nham Vu