Home Page
About
Chemogenesis Web Book
Chemical Thesaurus
Tutorials and Drills
Shop
Reviews
Contact
Links
Frequently Asked Questions

pre 1900 formulations
1900 to 1949 formulations
1950 to 1999 formulations
2000 to 2009 formulations
Spiral formulations
3 dimensional formulations
Data mapping periodic tables
Miscellaneous periodic tables
Books and reviews
non-chemistry periodic tables
All periodic tables


The INTERNET
Database of Periodic Tables

There are hundreds of periodic tables in web space, but there is only one comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Dr Mark R Leach.

pre 1900 formulations 1900 to 1949 formulations 1950 to 1999 formulations 2000 to 2009 formulations Spiral formulations 3 dimensional formulations
Data mapping periodic tables Miscellaneous periodic tables Books and reviews non-chemistry periodic tables All periodic tables


1925

Sommerfield's Electon Filling Diagram

Arnold Sommerfeld diagram appears in an issue of Memoirs and Proceedings of the manchester Literary and Philosophical Society for 1925-26. volume 70, p. 141-151.

Eric Scerri writes:

"The electron groupings are not exactly the same as what is believed to exist today but it amounts to the same order of filling. For example p orbitals were thought to consist of two groups of 2 and 4 electrons, rather than 2, 2, 2 as believed today. Similarly d orbitals were thought to be formed of two groups of 4 and 6 electrons. With that in mind you will see that Sommerfeld was the first to propose an aufbau filling system: The occupation of 4s before 3d or as represented here the 2 electrons in orbit 11 followed by the 4 and 6 from orbits 3,s and 3,3.

"Sommerfeld does indicate sub-shells. They are just not the same groupings as the current ones. For example 2,1 and 2,2 indicates subshells within the 2nd main shell. Similarly the 3rd shell is presented as 3,2 and 3,3. The totals are of course the same, namely 6 for what we now call p orbitals and 10 for what we call d orbitals. All this came before the discovery of the 4th or spin quantum number. This is in keeping with Bohr's original assignment of shells and sub-shells.

"The discovery of sub-structure to electron shells was not an 'all or nothing' development, but a gradual and almost organic evolution."

Eric has a new book out – A Tale of Seven Scientists and a New Philosophy of Science – in which the gradual evolution of electronic structure involving Bohr, Sommerfeld, Bury, Main Smith, Pauli and others is traced out.

Thanks to Eric Scerri for the tip! 
See the website EricScerri.com and Eric's Twitter Feed

Top of Page


pre 1900 formulations 1900 to 1949 formulations 1950 to 1999 formulations 2000 to 2009 formulations Spiral formulations 3 dimensional formulations
Data mapping periodic tables Miscellaneous periodic tables Books and reviews non-chemistry periodic tables All periodic tables

Periodic Table, What is it showing?
Binary Compounds

© Mark R. Leach 1999-


Queries, Suggestions, Bugs, Errors, Typos...

If you have any:

Queries
Comments
Suggestions or periodic table representations not shown on this page
Suggestions for links
Bug, typo or grammatical error reports about this page,

please contact Mark R. Leach, the author, using mrl@meta-synthesis.com

This free, open access web book is an ongoing project and your input is appreciated.