Traditionally, the names of all noble gases end in "-on", with the exception of helium, which was not known to be a noble gas when discovered. The IUPAC guidel

Traditionally, the names of all noble gases end in "-on", with the exception of helium, which was not known to be a noble gas when discovered. The IUPAC guidelines valid at the moment of the discovery approval however required all new elements be named with the ending "-ium". A new IUPAC recommendation published in 2016 recommends using the "-on" ending for new group 18 elements, no matter whether they turn out to be a noble gas or not. In June 2016 IUPAC announced that it planned to give the element the name oganesson (symbol: Og), in honour of the Russian nuclear physicist Yuri Oganessian, and the name became official on 28 November 2016. Source: https://en.wikipedia.org/wiki/Oganesson https://en.wikipedia.org/wiki/Oganesson