118OgOganessonnoble gas
Atomic weight[294] [mass number]conventional

Oganesson(Og)

Oganesson (Og) is a noble gas in period 7 of the periodic table. Its properties reflect its electron configuration and position among neighbouring elements.

noble gasGroup 18Period 7p-blockunknown at STP
Position:Period 7, Group 18, Block p• Grid7:18[Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶

KEY PROPERTIES

Atomic number
118
Atomic weight
[294][longest-lived mass]
Category / Block
noble gas • p-block
Group / Period
18 / 7
Electron configuration
[Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶
State at STP
unknown(STP (0 °C, 100 kPa))

Electron configuration & shells

[Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶

28183232188

Shell model is schematic — see lesson on atomic structure for orbitals. Oxidation states: 0. Common ions: Og.

Measured properties

Values at stated conditions; missing data shown as “—”. Radii distinguished by type; densities at stated phase/temperature.

Electronegativity (Pauling)
First ionization energy
830 kJ·mol⁻¹ (first ionization, gas phase)
Atomic radius
152 pm (calculated)
Covalent radius
152 pm (covalent)
Van der Waals radius
Density
Melting point
Boiling point

Standard conditions: 1 atm unless noted. Values with null are not established or not comparable across allotropes. Radii are distinguished by type. Densities at stated phase/temperature.

Isotopes — Oganesson
Mass numberAbundanceStabilityHalf-life
294trace/syntheticradioactivesynthetic — longest-lived isotope

Isotopic abundances are natural terrestrial values where applicable; synthetic isotopes shown as trace.

Occurrence & uses

Occurs naturally; abundance and extraction depend on geochemistry. For heavy synthetics (Z > 92), no natural occurrence.

  • Industrial use
  • Laboratory reagent
  • Research

Discovery

JINR–LLNL collaboration — 2002

Safety

Consult SDS for compounds of this element; elemental hazards depend on form and exposure. This entry summarises the element, not every compound.

SOURCES

  1. [nist-atomic-weights]nist-atomic-weights (2022)/#nist-atomic-weights
  2. [nist-2022]nist-2022 (2022)/#nist-2022
  3. [iupac-gold]iupac-gold (2022)/#iupac-gold

Last reviewed: 2026-08-22 • Reviewer: dr-example

POPULAR SEARCHES

Start typing to search

Search lessons, formulas, calculators, glossary, and elements. Try “pH”, “stoichiometry”, or “molar mass”.

Open full search →