Oganesson

Oganesson (chemical symbol: Og) is a chemical element with atomic number 118, the number of protons in its nucleus. It is the highest-numbered element officially recognized to date. It does not occur naturally; it has been created in laboratories using particle accelerators that collide atomic nuclei.

The element is named after the Russian physicist Yuri Oganessian, who led extensive work on the synthesis of superheavy elements. The official name was adopted in 2016 by international bodies responsible for naming chemical elements.

Synthesis

The method used involves bombarding a heavy element nucleus with high-energy projectiles, so that the two nuclei fuse and create a new, heavier nucleus. The main work was carried out at the nuclear research institute in Dubna, Russia, in collaboration with American laboratories. The atoms produced are extremely few in number, which makes it difficult to study their chemical properties directly.

Properties and half-life

Oganesson is highly unstable: its nuclei decay in extremely short periods, estimated at fractions of a millisecond, emitting alpha particles. For this reason, much of what is known about its properties rests on computational and theoretical models rather than direct experiment.

Position in the periodic table

In the periodic table, oganesson occupies the seventh period in group 18, the noble gases, alongside helium, neon, and radon. However, chemical and physical theory suggests that it may not behave exactly like the other noble gases in this group, owing to relativistic effects on its electrons. Some researchers have predicted that under normal conditions it might be a solid rather than a gas.