Oganesson (Og)
Unknown / predicted · p-block · period 7 · group 18
Never seen; predicted to be a solid, not a gas.
Oganesson (symbol Og) is chemical element number 118, a unknown / predicted in group 18, period 7 of the periodic table. Its standard atomic weight is (294) and its electron configuration is [Rn] 5f14 6d10 7s2 7p6. Its state at room temperature is unknown, and it is radioactive. The heaviest element yet made, and the last box in period 7.
Properties
| Atomic number | 118 |
|---|---|
| Atomic mass | (294) |
| Category | Unknown / predicted |
| Block | p-block |
| Group · Period | 18 · 7 |
| Electron configuration | [Rn] 5f14 6d10 7s2 7p6 |
| Electrons per shell | 2, 8, 18, 32, 32, 18, 8 |
| State at 25 °C | unknown |
| Melting point | — |
| Boiling point | — |
| Density | — |
| Electronegativity (Pauling) | — |
| Radioactive | Yes — no stable isotope |
| Origin | synthetic |
| Discovered | 2002 · Dubna / Livermore |
Key facts about Oganesson
- The heaviest element yet made, and the last box in period 7.
- Named after Yuri Oganessian, still living — only the second element named after a living person.
- Formally a noble gas, but predicted to be a reactive solid at room temperature.
- Only about five atoms have ever been detected, each lasting under a millisecond.
What Oganesson is used for
None — pure research into the limits of the periodic table.
Where it sits in the periodic table
Oganesson is in group 18, period 7, of the p-block. Its electron configuration [Rn] 5f14 6d10 7s2 7p6 means its outermost shell holds 8 electrons, which is what places it here and explains much of its chemistry. See Oganesson on the interactive table →
Oganesson — frequently asked questions
What is Oganesson used for?
None — pure research into the limits of the periodic table.
Is Oganesson radioactive?
Yes. Oganesson has no stable isotope, so every form of it is radioactive.
What is the electron configuration of Oganesson?
Oganesson has the electron configuration [Rn] 5f14 6d10 7s2 7p6, which is 2, 8, 18, 32, 32, 18, 8 electrons per shell.
What group and period is Oganesson in?
Oganesson is in group 18, period 7, in the p-block. Its outer shell holds 8 electrons.
Who discovered Oganesson?
Oganesson was discovered in 2002 by Dubna / Livermore.