Skip to content
Og

Oganesson

Oganesson is a chemical element with the symbol Og and atomic number 118. It has a mass number of 294, sits in period 7 and group 18, and is classified as a noble gas.

Properties

SymbolOg
Atomic number118
Mass number294
CategoryNoble gas
Group18
Period7
Electron configuration[Rn] 5f14 6d10 7s2 7p6
Outer-shell electrons8

The figure of 294 is a mass number rather than a measured atomic weight, because this element has no stable isotope.

Calculate with oganesson

Group 18

Atomic weights are the IUPAC 2021 standard values, abridged to the conventional five significant figures. Group, period, category and electron configuration are derived from the atomic number rather than stored, so they cannot drift out of step with it.