Oganesson (Og)
“The heaviest element ever made — and only the second in history named after a living scientist: Yuri Oganessian, whose calcium-48 beams made it possible.”
How its electrons are arranged
Computed from the aufbau principle, with known real-world exceptions applied automatically.
The notes
Characteristics
- The heaviest atom ever assembled — 118 protons — yet fewer than ten atoms of oganesson have ever been made, each lasting less than a millisecond.
- Its Og-294 alpha-decay chain runs down through livermorium and flerovium to known nuclei — that genealogy is the very proof of its existence.
- Relativity is predicted to smash the usual shell structure: calculations show puffed-up, smeared electron shells with none of the crisp layers of radon or xenon.
- Its enormous polarisability means oganesson could be the first noble gas that is a solid at room temperature — and perhaps eager enough to form real compounds.
Fewer than ten atoms of oganesson have ever existed, each vanishing in under a millisecond. Though it sits in the noble-gas column, relativistic calculations predict something no noble gas has ever been: a solid, hugely polarisable, probably reactive substance whose electron shells are so puffed up and smeared that they lose their neat layer structure.
Where you meet it
✦ Uses
- The ultimate benchmark for relativistic quantum chemistry: predictions such as a solid, reactive, shell-smeared oganesson dare theorists to get the numbers right at the table’s edge.
- Probing the far shore of the island of stability: Og-294’s sub-millisecond lifetime shows how nuclear stability fades as Z climbs beyond 114.
- Its rare decay chains help calibrate the detectors of Dubna’s new Superheavy Element Factory, now hunting elements 119 and 120.
- The Ca-48 + Cf-249 recipe that made oganesson is the template for every future hot-fusion attempt at new elements.
◍ Everyday examples
- The November 2016 announcement completed the 118-element periodic table — for the first time since 1869 every one of the seven periods stood finished, and chemistry classrooms from Dhaka to Dublin received updated charts.
- Oganesson answers one of chemistry’s rarest quiz questions: name a scientist honoured by an element while still alive — Glenn Seaborg (seaborgium) and Yuri Oganessian (oganesson) are the only two.
- The very last box of the NCTB periodic chart — bottom-right of the seventh row — belongs to oganesson, symbol Og.
History & name
After a 1999 Berkeley claim to element 118 collapsed in a data-fabrication scandal, the Dubna–Livermore team led by Yuri Oganessian went after the real thing: calcium-48 ions onto a californium-249 target produced the first atoms in 2002, and in October 2006 they announced oganesson-294 — three decay chains in all. IUPAC recognised the discovery in December 2015, and in November 2016, with the naming of oganesson closing the seventh period and completing the 118-element table, the element took the name of a living legend: Yuri Oganessian, head of Dubna’s Flerov Laboratory, only the second person after Glenn Seaborg to be honoured with an element in his own lifetime.