Tennessine honours the American state of Tennessee, home to the Oak Ridge National Laboratory, the University of Tennessee and Vanderbilt University, whose contribution, above all the production of the rare berkelium target essential to the synthesis, made the element possible. Its name ends in -ine rather than the usual -ium, following the convention for the halogens, the family of fluorine, chlorine, bromine, iodine and astatine in which element 117 sits, though whether so heavy an element truly behaves like a halogen remains a theoretical question.
Tennessine was the last of the four elements whose confirmation in 2016 completed the seventh period of the periodic table, filling the final gap in the seven known rows. It has no ancient or esoteric tradition, being a synthetic element of the twenty-first century; its name marks the American laboratories' part in finishing the table. Theoretical calculations suggest tennessine might turn out to be the first metallic halogen, its heavy, relativistically distorted electron cloud predicted to give it a duller shine and a shift toward metal-like bonding quite unlike the volatile, sharply coloured lighter halogens fluorine, chlorine, bromine and iodine, though with atoms surviving only milliseconds, testing that prediction directly remains far beyond current experimental reach.