150 years since Mendeleev

Yoshiteru Maeno
Department of Physics, Graduate School of Science, Kyoto University, Japan
Thursday, October 31, 2019
3:30 pm
RH 101
2019 has been designated by UNESCO as the International Year of the Periodic Table (IYPT2019), marking the 150th anniversary since Dmitry Mendeleev discovered the Periodic System. The arrangement of elements in Mendeleev’s short-period periodic table reflects how each element forms oxides and hydrides. In contrast, the long-period table widely used now expresses configuration of electron orbitals. It is much less known that it was introduced as early as in 1905 by a Swiss chemist, Alfred Werner [1]. In addition to many other variations of the periodic tables proposed, there have also been efforts to better represent the periodicity in three-dimensional forms.
In this talk, I will briefly review these efforts to improve the periodic table since Mendeleev’s version, in special focus on the three-dimensional versions. I will then describe how the three-dimensional periodic table “Elementouch” can resolve some of the shortcomings of the widely-used Werner’s table [2]. Namely, (1) all the elements are arranged continuously, (2) grouping of elements based on their chemical valences as in Mendeleev’s table is recovered, and (3) electron orbitals can be visualized better. 
*Note from speaker:
Please bring a pair of scissors and a scotch tape. I will ask each you to assemble the “Elementouch” (it is simple!) yourself during the colloquium, so that you can examine how Mendeleev’s periodic system is recovered in a modern periodic table.

[1] J. W. van Spronsen, “The periodic system of chemical elements”, Elsevier (1969).
Presented at Japanese Physical Society Meeting, March, 2002; and at American Physical Society Meeting, March, 2010.
Jing Xia