Finally, Glenn Seaborg proposed the f-series (Actinide Series) based on his research on Americium and Curium. Combined with Pauli’s exclusion principle a quantum rule for filling electron shells was determined. This was further adapted into the Bohr model. This led to the octet rule and valence bond theories. In 1914 Johannes Rydberg determined a relationship in the atomic numbers of noble gases. Skipping ahead to 1913, Anton van den Broek, proposed the nuclear charge determined the placement in the Periodic Table. This 8-column format was used for decades, even after other formats were developed. By 1871 Mendeleev had a Periodic Table in eight groups related to oxidation states. Mendeleev’s gap for Gallium ( Eka-Aluminium) is a well-known example. Mendeleev left gaps where there was no known element matching the anticipated weight and properties.
Frequently incorrect weights were reported and later revised when purer samples could be analyzed. He was correct because many elements were difficult to isolate in the samples at the time. Mendeleev trusted experimental evidence of chemical reactions more than the measured weights. He used atomic weights to sort the elements however, he reordered them based on observed properties if they did not seem to be in the right spots. In 1863 Dmitri Mendeleev drafted the first of his 60 versions of the Periodic Table. He observed there were similar properties every eight elements, so he organized his table with eight columns. John Newlands organized elements based on weights. Let us take a brief look at both the history and the most common versions in use today.
While the information about each element in the Periodic Table is the same, different formats have been used to organize the Periodic Table. Hmmm, is this element a Ravenclaw or Hufflepuff? Versions of the Periodic Table For Harry Potter fans, think of it as an algorithmic version of a sorting hat. The organization of the Periodic Table in Rows and Columns is not haphazard.
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