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The INTERNET Database of Periodic Tables

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

Use the drop menus below to search & select from the more than 1300 Period Tables in the database: 

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Year:  1916 PT id = 1214

Sommerfeld's Periodic Table

A periodic table by Arnold Sommerfeld, as an updated construction by Marks & Marks (2021).

John Marks writes:

"The reconstruction of Sommerfeld 1916 is derived from my reading of Henry Browse's translation of the third German edition of his Atomstruktur und Spektrallinien (Methuen 1923). Sommerfeld found the explanation of the greater (d– and f–) and lesser (s– and p–) periods in the solution of Kepler's ellipses using Schwarzschild's relativistic correction, communicated to him from the battlefront of WW1. Sommerfeld considered helium "an exception" but this is only an appearance deriving from defining periods as terminated by inert gases. In fact, the first period begins with hydrogen so the markers of periods are analogues of hydrogen, viz. the halogens."

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What is the Periodic Table Showing? Periodicity

© Mark R. Leach Ph.D. 1999 –

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