Oganesson, atomic number 118, is the last element of the periodic table, at least for the time being. It is named for Yuri Oganessian who led the team at the Russia’s Joint Institute for Nuclear Research in the discoveries of six elements, oganesson included.
Oganesson has, in theory, seven electron shells with a full outer valence shell of eight electrons. In reality the shells are unlikely to be neatly nested (because of the perturbations caused by oganesson’s huge nucleus), but the metaphor of a Russian doll was too nice to resist.
It will be interesting to see how long my periodic table remains current. Do I have the constitution of Group III correct? The most recent IUPAC periodic table still hedges its bets with 15 elements in each of the lanthanoids and actinoids. And when will the next element be discovered to begin period 8?