 Like its neighbors in the periodic table, tennessine is expected to have the lowest electron affinity—energy released when an electron is added to the atom—in its group; 2.6 or 1.8 eV.The electron of the hypothetical hydrogen-like tennessine atom—oxidized so it has only one electron, Ts116+—is predicted to move so quickly that its mass is 1.9 times that of a non-moving electron, a feature attributable to relativistic effects.For comparison, the figure for hydrogen-like astatine is 1.27 and the figure for hydrogen-like iodine is 1.08.