Periodic Table |
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| What is the Periodic Table Showing? | Periodicity |
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. The database holds information on periodic tables, the discovery of the elements, the elucidation of atomic weights and the discovery of atomic structure (and much, much more).
| Year: 2023 | PT id = 1280, Type = formulation |
Marks' Version of Mendeleyev's 1869 Formulation
John Marks, who provided the graphic, writes:
"I went back to Mendeleyev´s 1869 original and drew this (below) which demonstrates the Sommerfeldsche aufspaltung as occurring after completed s-subshells. No-one disputes the chemical phenomena of the octets formed by He/Ne, Li/Na, Be/Mg, B/Al, C/Si, N/P and O/S nor that H/F occurs at the beginning of these octets, however "irregular" H may appear.
"Chemical periodicity is clearly based on periods arising from sp3 hybridization and the aufspaltung appears to occur between the s and the p3. This gives rise to the positions of Sommerfeld's "Long" (with the d-elements) and "Very Long" (with the f-elements) periods."

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| What is the Periodic Table Showing? | Periodicity |
© Mark R. Leach Ph.D. 1999 –
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