Periodic Table |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
| 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: 2022 | PT id = 1234, Type = formulation spiral |
Kudan's Periodic Law (Helix Form)
From Pavel V. Kudan, a specialist in mass-spectrometry and identification of compounds, who suggests a helical variant of the Periodic table. The graphical representation illustrates the Periodic Law and the following features of the Kudan’s periodic system:
- Four element periods (1, 2, 3, 4)
- Two element half periods (-,+)
- Twenty one element subgroups octet rule compatible (1a-8a, 2b-8b, 3c-8c)
- Small energy barriers between S and F, F and D, D and P elements (gray segments)
- Large energy barriers between P and S elements (black segments)
- Large energy barrier between He and Li (black segments)
(See also Kudan’s Left-Step Periodic Table)

![]() |
![]() |
![]() |
| What is the Periodic Table Showing? | Periodicity |
© Mark R. Leach Ph.D. 1999 –
Queries, Suggestions, Bugs, Errors, Typos...
If you have any:
Queries
Comments
Suggestions
Suggestions for links
Bug, typo or grammatical error reports about this page,please contact Mark R. Leach, the author, using mark@meta-synthesis.com
This free, open access web book is an ongoing project and your input is appreciated.






