Two isotopes of a modern element with atomic number Z=117 were created by an international collaboration in the reaction between unique radioactive 249Bk target material produced at ORNL through the DOE Isotope Program and an intense beam of 48Ca ions at the Joint Institute for Nuclear Research (Dubna,Russia). This result completed the 7th row of the Periodic Table of Elements and demonstrated the existence of long-sought Island of Stability for superheavy nuclei, originally proposed by Glenn Seaborg in the 1960s.
Source: phys.org