Several years after their discovery, on 28th November 2016., Nihonium, Moscovium, Tennesine and Oganesson were officially declared new elements and thus part of the yet again improved Periodic system of elements.

For millenniums our civilization has been developing and discovering new elements, especially after the 18th and in the 20th century until the present, when the development of science and technology and the symphony of the two has enabled us to discover, that is, to make synthetic elements (elements which can not be found in nature as we know it, but can be produced in a laboratory). All synthetic elements are extremely radioactive and unstable, to the extent that it’s barely possible to discover them difficult to produce them, since it takes only few seconds or microseconds for them to decay and reduce to half their initial value (a.k.a. half-life). Nihonium, with the atomic number of 113, was first discovered back in 2003. on the Russian institute JINR and again in 2004 on the Japanese institute RIKEN. IUPAC (International Union of Pure and Applied Chemistry, an international organization which encourages the development of chemistry and represents the chemists of individuals countries) decided that Japan was to get credit for the discovery, hence the name for the element originating for the word Nihon; Japanese word for “the land of the raising sun”. Oganesson, Moscovium and Tennessine were all discovered on JINR with the collaboration of Russian and American scientific teams. Oganesson was discovered in 2002. and is yet another element in the tradition of naming elements after scientist, in this case particularly after the great nuclear physicist Yuri Oganessian with the atomic number of 118, and is the last element of the 7th period, therefore also the heaviest element yet discovered (heaviest as in the biggest number of protons, not by its density). Moscovium, with the name’s apparent connection to Moscow (Russia’s capital and the emplacement of JINR), with atomic number of 115 was discovered in 2003. Tennessine, the youngest of four elements, being discovered in 2010., is also the second heaviest element known with its atomic number of 117, alongside being famous for its radioactivity and toxicity. Even though they were discovered ages ago, it wasn’t before November of 2016. that IUPAC and IUPAP (International Union of Pure and Applied Physics, an organisation of the same kind as IUPAC, the focus being on physics) officially declared the discovery of the four elements, on account of not being able to determine the exact properties of the elements due to their unstableness, which evidently meant not being able to place them in the PSE. Once everything was resolved, on 28th November 2016., the names and positions of Nihonium, Moscovium, Tennesine and Oganesson were officially acknowledged and so began an era of a yet better and newer PSE. With these four elements the chapter is closed for the seventh period of PSE, and scientists are already discovering the possibility of other undiscovered elements, for now and probably for another few years, just theoretical.

Blanka Ivanović, Vladimir Prelog Science School, Zagreb