oganesson /oʊɡəˈnɛsɒn/ noun2 •The chemical element (symbol Og) with atomic number 118. It is the heaviest known element. Highly radioactive, it does not occur naturally. Originally expected to be a noble gas, it is now predicted to be a reactive metallic solid, and a semiconductor or a post-transition metal.SINGAPORE - The four new elements announced in December last year have received their new names: Nihonium (Nh), moscouvium (Mc), tennessine (Ts) and oganesson (Og). — 2016 •An atom of this element.
