Electronic Structure at the Edge of the Periodic Table

Theoretical investigation of atomic and chemical properties of the elements at the low edge of the periodic table, called transactinide or superheavy elements (SHEs), sheds light on the effects of relativity on their electronic structure, revealing significant modification of the known regularities of the Periodic Law. The experimental study of the SHEs is targeting mainly the development of extreme (“atom-at-a-time”) chemistry and spectroscopy. The updated periodic table contains seven full periods with 118 elements, including 15 transactinides or super-heavy elements, from the lightest rutherfordium (Z = 104) to the heaviest, recently named oganesson (Z = 118). There have been attempts to synthesize the next transactinide elements with atomic numbers 119 and 120, starting the eighth period of the periodic table [1], but the very low cross-sections (below 0.4 pb) frustrated these efforts. In order to increase the production rate of the known SHE isotopes by one or two orders of magnitude, required for successful synthesis of new elements with Z > 118, a new and unique experimental complex, the SHE Factory, has recently been established in Dubna. This facility is expected to make substantial breakthroughs in the physical and chemical research of the heaviest nuclei and elements; the first experiments are already planned for 2019 [2].