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 hold information on periodic tables, the discovery of the elements and elucidation of atomic weights (and more).
| Year: 2004 | PT id = 143, Type = data misc |
Biologist's Periodic Tables
A periodic table showing where biologically essential (green), essential trace (purple), toxic (red), radioactive (yellow) and of low but not zero biological impact (gray) elements are found. Only highly toxic elements are shown in red. Li (as Li+) is biologically active and is used as an antidepressant.

By Mark Leach
or here:
And a periodic table for biologists from Science Videos:
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| What is the Periodic Table Showing? | Periodicity |
© Mark R. Leach Ph.D. 1999 –
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