Editing Extended periodic table (section)

===Pyykkö===
[[Pekka Pyykkö]] used computer modeling to calculate the positions of elements up to ''Z''&nbsp;=&nbsp;172 and their possible chemical properties in an article published in 2011. He reproduced the orbital order of Fricke et al., and proposed a refinement of their table by formally assigning slots to elements 121–164 based on ionic configurations.<ref name="PT172">{{Cite journal|last1=Pyykkö|first1=Pekka|s2cid=31590563|author-link=Pekka Pyykkö|title=A suggested periodic table up to Z≤ 172, based on Dirac–Fock calculations on atoms and ions|journal=Physical Chemistry Chemical Physics|volume=13|issue=1|pages=161–8|year=2011|pmid=20967377|doi=10.1039/c0cp01575j|bibcode = 2011PCCP...13..161P }}</ref>
[[File:Pyykko periodic table 172.svg|thumb|center|512px]]
In order to bookkeep the electrons, Pyykkö places some elements out of order: thus 139 and 140 are placed in groups 13 and 14 to reflect that the 8p<sub>1/2</sub> shell needs to fill, and he distinguishes separate {{not a typo|5g}}, 8p<sub>1/2</sub>, and 6f series.<ref name=PT172/> Fricke et al. and Nefedov et al. do not attempt to break up these series.<ref name=actrev/><ref name=nefedov/>