JERIES A. RIHANI
Let us assume that the nuclei of the elements, including their corresponding atomic structure, beyond element 118 are experimentally synthesizable. Let us further assume that the Aufbaue Principle in its extrapolated form also holds and applies even at this highly unstable and complex nuclear and chemical stage. If these assumptions were granted then we could perhaps argue that the question of extending the periodic table of the elements (to include at least two or three elements beyond element 122) necessarily may narrow down to one basic issue and that is our detailed understanding of the way the atomic orbitals (at the ground state) tend to become either half-filled or completely-filled orbitals, as a net result of seeking lowest possible energy levels. For example, we know that at certain appropriate instances or occasions, the d orbital, within any relevant electron period (electrons in orbitals very close in energy levels,i.e., 7s<5f<6d<7p or 8s<5g<6f<7d<8p), chooses to receive an electron from the s orbital within the same period in order to satisfy this tendency (as in the electron configurations of Cr, Cu, Mo, Ag, Au, Uuu, Uhu). By comparison, the f orbital, in seeking to satisfy the same tendency in similar occasions, chooses to receive this required electron from the d orbital, its closest in energy level within the same period (as in the electron configurations of Eu, Yb, Am, No, Uqp, Upb).
Now, here is the big question. What happens when it is g's turn? Should the g orbital, in seeking the same, receive this 'occasional electron' from d again (as is the case with f) or should it receive it from, its closest, the f? Or, for that matter, when it is h's turn in the period 10s<6h<7g<8f<9d<10p, should the h orbital, in seeking the same again, pick its 'occasional electron' from d, .. from f, or from, its closest, the g?
At this point in the developmental stage of the periodic table it is helpful to know that we can put aside the question regarding h and focus on g alone. In fact, finding the answer for g can undoubtedly help us extrapolate and predict the answer regarding h (theoretically at least)*.
As you can see, answering the question regarding g leads us to two possible answers and, at this stage, we do not know which one answer is correct. Thus, if g behaves in a similar fashion as f and needs (in certain instances or occasions) to get its electron from d, we have no problem with that because d already has one electron available to donate as is shown in the extended periodic table suggested by Glenn T. Seaborg. On the other hand, if g must get its 'occasional electron' from f, we face a problem because f is empty at this stage and, hence, has nothing to give. However, and in order to overcome this difficulty, we can see, prior to dealing with g and based on lower energy considerations, how it is possible for one electron to fall initially in f (the 'occasional electron' g needs at certain appropriate occasion) and then, progressively afterwards, how g can start filling with its set of electrons as is shown in the extended periodic table suggested by Jeries A. Rihani.
In 1984, I made two layouts, on independent sheets of paper, for two different extended periodic tables corresponding to the two different possible answers for g suggested above. However, instead of including both versions in the appendix of the two studies published by The Royal Scientific Society in Amman I included only one. I was hoping that someday this extended form might draw the attention of somebody interested in the same issue and perhaps initiate some sort of a debate in order to resolve the issue. Unfortunately, this debate has never been realized and the issue still stands unresolved.
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*Reaching the h-block stage is highly improbable and it seems likely the periodic table may reach an end at a much earlier stage either at atomic number 120 or 170.
[THE ABOVE COMMENTARY, SLIGHTLY MODIFIED, WAS TAKEN FROM AN E-MAIL MESSAGE SENT BY THE AUTHOR, ON AUGUST 5, 1999, TO DR. HISHAM B. GHASSIB, THE ROYAL SCIENTIFIC SOCIETY, AMMAN, JORDAN.]
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