 Significant differences between tennessine and the previous halogens are likely to arise, largely due to spin–orbit interaction—the mutual interaction between the motion and spin of electrons.The spin–orbit interaction is especially strong for the superheavy elements because their electrons move faster—at velocities comparable to the speed of light—than those in lighter atoms.In tennessine atoms, this lowers the 7s and the 7p electron energy levels, stabilizing the corresponding electrons, although two of the 7p electron energy levels are more stabilized than the other four.