Is the Periodic Table all right (“PT OK”)?

The Periodic Electronegativity Table

The origins and development of the electronegativity concept as an empirical construct are briefly examined, emphasizing the confusion that exists over the appropriate units in which to express this quantity. It is shown how to relate the most reliable of the empirical scales to the theoretical definition of electronegativity in terms of the quantum potential and ionization radius of the atomic...

Cracks in the periodic table.

From the Mendeleev periodic table to particle physics and back to the periodic table

We briefly describe in this paper the passage from Mendeleev’s chemistry (1869) to atomic physics (in the 1900’s), nuclear physics (in the 1932’s) and particle physics (from 1953 to 2006). We show how the consideration of symmetries, largely used in physics since the end of the 1920’s, gave rise to a new format of the periodic table in the 1970’s. More specifically, this paper is concerned with...

PT -Symmetric Periodic Optical Potentials

In quantum theory, any Hamiltonian describing a physical system is mathematically represented by a self-adjoint linear operator to ensure the reality of the associated observables. In an attempt to extend quantum mechanics into the complex domain, it was realized few years ago that certain non-Hermitian parity-time (P T ) symmetric Hamiltonians can exhibit an entirely real spectrum. Much of the...

The heuristic account and the periodic table

In 2001, Worrall and Scerri critically reviewed claims held by philosophers and historians of science (Maher 1988, Lipton 1991, Brush 1996) that the acceptance of Dimitri Medeleev’s periodic table within the scientific community was strongly influenced by the prediction of novel elements made by Mendeleev based on “gaps” within the table. The intuition behind these claims has to do with the jus...