From telluric helix to telluric remix

Abstract

The first attempt to represent the Periodic system graphically was the Telluric Helix (Vis Tellurique) presented in 1862 by Alexandre-Emile Béguyer de Chancourtois, in which the sequence of elements was wound round a cylinder. This has hardly been attempted since, because the intervals between periodic returns vary in length from 2 to 32 elements, but Charles Janet presented a model wound round four nested cylinders. The rows in Janet’s table are defined by a constant sum of the first two quantum numbers, n and l, so that they end with the s-block, headed by hydrogen and helium. By combining Janet’s table, Edward Mazurs’ version, in which each row represents an electron shell and Valery Tsimmerman’s use of a half square for each element, I have produced a representation that can be printed out and wound round to make a cylinder with manageable dimensions. In the unwound version, I have placed the s-block in the middle, to emphasise its pivotal nature, since it both ends each (n + ℓ) row and contributes electrons to the valence of elements in the next (n + ℓ) row; it thus does not necessarily belong either on the left or the right side of a table. The downward arrows that link subshells within each (n + ℓ) series graphically illustrate the Janet Effect (or Madelung Rule). To acknowledge my debt to Chancourtois, Janet, Mazurs and Tsimmerman, I call my design the ‘Telluric Remix’.