On the periodic table, the heaviest officially named element is oganesson.
Oganesson has atomic number 118, the highest atomic number currently assigned to an officially recognized element. It is placed in group 18, below the other noble gases, although its extremely short-lived atoms make its chemistry difficult to study directly.
The element was first reported by a collaboration involving scientists at the Joint Institute for Nuclear Research in Dubna and Lawrence Livermore National Laboratory. Its name honors nuclear physicist Yuri Oganessian, who contributed to the discovery of several superheavy elements. The name was officially approved in 2016.
Oganesson is synthetic: it does not occur naturally in usable quantities. Only a very small number of atoms have been made, and its known isotopes decay rapidly. It is often described as a noble gas because of its group placement, but predictions suggest that its heavy-atom behavior may differ significantly from lighter group-18 elements.