Periodic Table
T-Shirts & more
from the
meta-synthesis



Merch Store


previous home next

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: 

  Text Search:       




Year:  1950 PT id = 14, Type = formulation

The Modern Periodic Table

The modern periodic table is based on quantum numbers and blocks, here.

A periodic table can be constructed by listing the elements by n and l quantum number:

The problem with this mapping is that the generated sequence is not continuous with respect to atomic number atomic number, Z: Check out the sequence Ar to K, 18 to 19.

Named after a French chemist who first published in the formulation in 1929, the Janet or Left-Step Periodic Table uses a slightly different mapping:

While the Janet periodic table is very logical and clear it does not separate metals from non-metals as well as the Mendeleev version, and helium is a problem chemically.

However, it is a simple mapping to go from the Janet or Left-Step periodic table to a modern formulation of Mendeleev's periodic table:

 

On this page web, "full" f-block included periodic tables are shown wherever possible, as above.

However, the periodic table is usually exhibited in book and on posters in a compressed form with the f-block "rare earths" separated away from the s-block, p-block and d-block elements:

However, the compression used introduces the well known problem known as a "fence post error".

The effect is that:

La and Ac: move from f-block to d-block
Lu and Lr: move from p-block to f-block

Chemically, the elements can be fitted in and classified either way. Many thanks to JD for pointing the situation with the periodic table is a fence post error.

Mark Winter's Web Elements project, here, uses the formulation shown below:

Interestingly, the IUPAC periodic table separates out 15 lanthanides, La-Lu, and 15 actinides, Ac-Lr by leaving gaps in period 3 under Sc & Y:

This corresponds to:

By Mark Leach

Top of Page

previous home next
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.