<P> The first two elements of period 8 are expected to be ununennium and unbinilium , elements 119 and 120 . Their electron configurations should have the 8s orbital being filled . This orbital is relativistically stabilized and contracted and thus , elements 119 and 120 should be more like rubidium and strontium than their immediate neighbours above , francium and radium . Another effect of the relativistic contraction of the 8s orbital is that the atomic radii of these two elements should be about the same of those of francium and radium . They should behave like normal alkali and alkaline earth metals , normally forming + 1 and + 2 oxidation states respectively , but the relativistic destabilization of the 7p subshell and the relatively low ionization energies of the 7p electrons should make higher oxidation states like + 3 and + 4 ( respectively ) possible as well . </P>
what is the atomic number of the yet undiscovered element directly below ra in the periodic table
120