The INTERNET Database of Periodic Tables
|2019 has been designated the International Year of the Periodic Table as it is the 150th Anniversary of the formulation of Mendeleev's Tabelle I|
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.
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 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:
|Periodic Table, What is it showing?||
© Mark R. Leach 1999-
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