DatabaseThere are hundreds of periodic tables in web space, but
there is . only one comprehensive database of periodic tables & periodic system formulationsIf you know of an interesting periodic table that is missing, please contact the database curator: Dr Mark R Leach.
Above from Quam & Quam's 1934 review paper.pdf and below from Eric Scerri. Eric comments that the interesting features are: - A remarkably modern looking formulation in that it separates not only the transition metals but also the rare earths into separate blocks to give what we would now call a "long-form 32 column table". Except Werner guessed wrong as to how many rare earths exist, with the result that he shows 33 groups.
- This formulation is also interesting for showing an element between H and He and two elements before H.
- Werner computed the average gaps between atomic weights for the second through the fifth periods as 1.85, 2.4, 2.47 and 2.5, respectively.
- From this he extrapolated the gap for the first period as 1.5, which coincidentally was also half the difference between the atomic weights of H and He. Werner thus predicted a new element with atomic weight 2.5.
- Moseley's work of 1913 showed there were no elements before H and none between H and He.
© Mark R. Leach 1999-
If you have any:
This
counter started in 2011 |