Oganesson is a synthetic chemical element with symbol Og and atomic number 118. Oganesson has the highest atomic number and highest atomic mass of all known elements. The radioactive oganesson atom is very unstable, and since 2005, only five (possibly six) atoms of the isotope oganesson-294 have been created.
The element is named in honor of Yuri Oganessian. It was first created in 2002 at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia by a joint team of Russian and American scientists. In December 2015, it was recognized as one of four new elements by the Joint Working Party of the international scientific people at IUPAC and IUPAP. It was formally named on 28 November 2016. It had a previous name given by the IUPAC called "Ununoctium" meaning "one-one-eight" in Latin. This was a placeholder name until the element was discovered and a name was given. The possibility of a seventh noble gas, after helium, neon, argon, krypton, xenon, and radon, was considered almost as soon as the noble gas group was discovered. Danish chemist Hans Peter Jørgen Julius Thomsen predicted in April 1895, the year after the discovery of argon, that there was a whole group of chemically unreactive gases similar to argon that would link the halogen and alkali metal groups. He expected that the seventh of this series would end a 32-element period which contained elements like thorium and uranium and have an atomic weight of 292, close to the 294 now known for the first and only confirmed isotope of oganesson.
The chemistry of Oganesson can not be found because of how radioactive it is and how short its half-life is, which is only 0.69 milliseconds. However, predictions can be made based on properties the group has in common with each other. Since its a noble gas, it is predited that its going to be a diatomic molecule (it only pairs with itself).
|Mass number|| (unconfirmed: 295)|
|Oganesson in the periodic table|
|Atomic number (Z)||118|
|Group||group 18 (noble gases)|
|Electron configuration||[Rn] 5f14 6d10 7s2 7p6 (predicted) (predicted)|
|Electrons per shell||2, 8, 18, 32, 32, 18, 8 (predicted)|
|Phase at STP||solid (predicted)|
|Boiling point||350±30 K (80±30 °C, 170±50 °F) (extrapolated)|
|Density when liquid (at m.p.)||4.9–5.1 g/cm3 (predicted)|
|Critical point||439 K, 6.8 MPa (extrapolated)|
|Heat of fusion||23.5 kJ/mol (extrapolated)|
|Heat of vaporization||19.4 kJ/mol (extrapolated)|
|Oxidation states||(−1), (0), (+1), (+2), (+4), (+6) (predicted)|
|Covalent radius||157 pm (predicted)|
|Crystal structure|| face-centered cubic (fcc)|
|Naming||after Yuri Oganessian|
|Prediction||Niels Bohr (1922)|
|Discovery||Joint Institute for Nuclear Research and Lawrence Livermore National Laboratory (2002)|
|Main isotopes of oganesson|
It currently has no use because of how radioactive and short its half life is.
|Wikimedia Commons has media related to Oganesson.|
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