  In this article and beginning with the Dirac solution to the Hydrogen atom in
its ground state, the exact results corresponding to the expectation value of
the distance of the electron to the proton and the maximum probability distance
are found. For hydrogen-like atoms and in contrast to the non relativistic Bohr
radius and expectation values, for $Z=\frac{\sqrt3}{2}\frac{1}{\alpha}$ (close
to 118), the expectation distance to the nucleus is zero thus putting an end to
the periodic table for Z = 118 nicely matching the last element discovered
(Oganesson).
