Icon of chemistry: the periodic system of chemical elements in the new century (original) (raw)
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Editorial 8���Special Issue on the Periodic System of the Elements
2001
The publication of this special issue is a special pleasure for me since I have been carrying out research on the periodic system of the elements for some years. Whereas many readers may have first become intrigued by chemistry after seeing some striking demonstration in their childhood, or by playing around with a chemistry set, others like myself may have been taken by the elegance and complexity of the periodic system.
ON THE BASIS OF THE PERIODIC ELEMENT SYSTEM
Journal “Scientific Israel ‒ Technological Advantages", 2019
It is shown that the basis of the periodic system of elements is a cyclical change in the moment of distribution of valence electrons as one of the parameters of the inhomogeneity of the system. An approximate expression of this moment is found through the degree of filling of the outer shell of an atom and on its basis a graphical representation of a periodic law is proposed, taking into account its number, charge, atomic radius and distribution of valence electrons. The graph reveals the existence of additional periods ending in inert metals, not only in known elements but also in the group of lanthanides and actinides, allowing them to be organically incorporated into the periodic system. The consistency of such a representation of the classical and quantum models of atoms is shown.
A representation of the periodic system based on atomic-number triads
Foundations of Chemistry, 2018
In the last decade, the notion of triad was reintroduced by Eric Scerri, who suggested it as a possible categorical criterion to represent chemical periodicity. In particular, he reformulated the notion of triad in terms of atomic number instead of atomic weights; in this way, the value of the intermediate term of the triad became the exact average of the values of the two extremes. Following the inspiration of Scerri’s work, the main purpose of this article is to obtain a representation where all the relations among the chemical elements that form the groups of the periodic system can be reconstructed on the basis of triads, without using electronic configurations.
The value of vague ideas in the development of the periodic system of chemical elements
2021
The exploration of chemical periodicity over the past 250 years led to the development of the Periodic System of Elements and demonstrates the value of vague ideas that ignored early scientific anomalies and instead allowed for extended periods of normal science where new methodologies and concepts are developed. The basic chemical element provides this exploration with direction and explanation and has shown to be a central and historically adaptable concept for a theory of matter far from the reductionist frontier. This is explored in the histories of Prout’s hypothesis, Döbereiner Triads, element inversions necessary when ordering chemical elements by atomic weights, and van den Broeck’s ad-hoc proposal to switch to nuclear charges instead. The development of more accurate methods to determine atomic weights, Rayleigh and Ramsey’s gas separation and analytical techniques, Moseley’s x-ray spectroscopy to identify chemical elements, and more recent accelerator-based cold fusion met...
150 Years of the Periodic Table, Perspectives on the History of Chemistry, C. J. Giunta et al. (eds.), , 2021
The historical development of the theoretical account of the periodic table provided by theoretical physics is reviewed, beginning with discoveries made at the start of the twentieth century. The article highlights the attempts to theoretically explain several features of the periodic table including the well-known period doubling or Madelung rule of orbital occupation. The account includes more recent group theoretical approaches which go beyond quantum mechanics and seek an explanation based in the underlying symmetry of the periodic table and how this symmetry is broken to produce the diversity of atoms that we are familiar with. The approach taken is one of seeking a global solution to such questions rather than merely solving the equations of quantum mechanics for each individual case.