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: 1918 | PT id = 1300, Type = formulation |
One of Mendelejeff's Tables, Modified
From Smith A 1918, General Chemistry for Colleges, 2nd ed., The Century Co., New York, p. 299
René Vernon writes:
- H is missing, as are the noble gases.
- Consequently, the period numbers are out by one apiece.
- Seven groups are on the left and seven are on the right (the ever present allure of symmetry).
- After La, Ce is placed under Zr, and Nd is placed under columbium/technetium.
- According to Smith the rest of the lanthanide elements do not fit into any series, because their valences and other chemical properties do not permit most of them to be distributed over so many different groups.
- Po is expected to be a metal which is what it turned out to be Smith has anticipated that astatine will be a metal. Nine decades later, Hermann, Hoffmann & Ashcroft (2013) predicted the same thing: Hermann, A.; Hoffmann, R.; Ashcroft, N. W. (2013). Condensed astatine: Monatomic and metallic. Physical Review Letters, 111 (11), 116404-1–116404-5
- While he does not discuss it, Smith appears to have allowed for missing elements between Li and Gl and between Na and Mg.
- The three elements inside square brackets are those predicted by Mendeleev.

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