Editing Extended periodic table (section)

====Beyond element 172====
Beyond element 172, there is the potential to fill the 6g, 7f, 8d, 10s, 10p<sub>1/2</sub>, and perhaps 6h<sub>11/2</sub> shells. These electrons would be very loosely bound, potentially rendering extremely high oxidation states reachable, though the electrons would become more tightly bound as the ionic charge rises. Thus, there will probably be another very long transition series, like the superactinides.<ref name="BFricke"/>

In element 173 (unsepttrium), the outermost electron might enter the 6g<sub>7/2</sub>, 9p<sub>3/2</sub>, or 10s subshells. Because spin–orbit interactions would create a very large energy gap between these and the 8p<sub>3/2</sub> subshell, this outermost electron is expected to be very loosely bound and very easily lost to form a 173<sup>+</sup> cation. As a result, element 173 is expected to behave chemically like an alkali metal, and one that might be far more reactive than even [[caesium]] (francium and element 119 being less reactive than caesium due to relativistic effects):<ref name="BFricke1977">{{cite journal |last1=Fricke |first1=Burkhard |author-link=Burkhard Fricke |year=1977 |title=Dirac–Fock–Slater calculations for the elements Z = 100, fermium, to Z = 173 |url=http://kobra.bibliothek.uni-kassel.de/bitstream/urn:nbn:de:hebis:34-2008071622807/1/Fricke_Dirac_1977.pdf |journal=Recent Impact of Physics on Inorganic Chemistry |volume=19 |pages=83–192 |bibcode=1977ADNDT..19...83F |doi=10.1016/0092-640X(77)90010-9 |access-date=25 February 2016}}</ref><ref name=primefan>{{cite book |editor-last=Kolevich |editor-first=T. A. |last1=Kulsha |first1=Andrey |chapter=Есть ли граница у таблицы Менделеева? |trans-chapter=Is there a boundary to the Mendeleev table? |date=2011 |title=Удивительный мир веществ и их превращений |trans-title=The wonderful world of substances and their transformations |url=http://www.primefan.ru/stuff/chem/ptable/ptable.pdf |location=Minsk |publisher=Национальный институт образования (National Institute of Education) |pages=5–19 |isbn=978-985-465-920-6 |language=ru |access-date=8 September 2018}}</ref> the calculated ionisation energy for element 173 is 3.070&nbsp;eV,<ref name=eliav2023/> compared to the experimentally known 3.894&nbsp;eV for caesium. Element 174 (unseptquadium) may add an 8d electron and form a closed-shell 174<sup>2+</sup> cation; its calculated ionisation energy is 3.614&nbsp;eV.<ref name=eliav2023/>

Element 184 (unoctquadium) was significantly targeted in early predictions, as it was originally speculated that 184 would be a proton magic number: it is predicted to have an electron configuration of [172] 6g<sup>5</sup> 7f<sup>4</sup> 8d<sup>3</sup>, with at least the 7f and 8d electrons chemically active. Its chemical behaviour is expected to be similar to [[uranium]] and [[neptunium]], as further ionisation past the +6 state (corresponding to removal of the 6g electrons) is likely to be unprofitable; the +4 state should be most common in aqueous solution, with +5 and +6 reachable in solid compounds.<ref name="Fricke"/><ref name="BFricke"/><ref name=Penneman>{{cite journal |last1=Penneman |first1=R. A. |last2=Mann |first2=J. B. |last3=Jørgensen |first3=C. K. |date=February 1971 |title=Speculations on the chemistry of superheavy elements such as Z = 164 |journal=Chemical Physics Letters |volume=8 |issue=4 |pages=321–326 |doi=10.1016/0009-2614(71)80054-4 |bibcode=1971CPL.....8..321P }}</ref>