Recent attempts to change the periodic table Scerri, Eric
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
09/2020, Letnik:
378, Številka:
2180
Journal Article
Recenzirano
Odprti dostop
The article concerns various proposals that have been made with the aim of improving the currently standard 18-column periodic table. We begin with a review of 8-, 18- and 32-column formats of the ...periodic table. This is followed by an examination of a possible, although rather impractical, 50-column table and how it could be used to consider the changes to the periodic table that have been predicted by Pyykkö in the domain of superheavy elements. Other topics reviewed include attempts to derive the Madelung rule as well as an analysis of what this rule actually provides. Finally, the notion of an ‘optimal’ periodic table is discussed in the context of recent work by philosophers of science who have examined the nature of classifications in general, as well as the notion of natural kinds. The article takes an unapologetically philosophical approach rather than focusing on specific data concerning the elements. Nevertheless, some pragmatic issues and educational aspects of the periodic table are also examined.
This article is part of the theme issue ‘Mendeleev and the periodic table’.
How many candles?! The year 2019 has been named as the International Year of the Periodic Table in accordance with Mendeleev's work from 1869. In line with other celebratory events and articles to be ...found this year in Chemistry—A European Journal, here, Eric R. Scerri provides an historical account of the development of the periodic table and some of the debates and considerations surrounding this fundamental elementary ensemble.
The article examines a recent interventionist account of causation by Ross, in which electronic configurations of atoms are considered to be the cause of chemical behavior. More specifically I ...respond to the claim that a change in electronic configuration of an atom, such as occurs in the artificial synthesis of elements, causes a change in the behavior of the atom in question. I argue that chemical behavior is governed as much by the nuclear charge of an atom as it is by its electronic structure. It is suggested that an adequate analysis requires attention to the dynamical interactions between nuclear charges and those of electrons, as typically carried out through the application of the Schrödinger equation. It is concluded that electronic configurations can only be said be causal in a weak sense that is somewhat analogous to the causal arguments that are invoked in folk physics.
For a period of several years the philosopher of science Hasok Chang has promoted various inter-related views including pluralism, pragmatism, and an associated view of natural kinds. He has also ...argued for what he calls the persistence of everyday terms in the scientific view. Chang claims that terms like phlogiston were never truly abandoned but became transformed into different concepts that remain useful. On the other hand, Chang argues that some scientific terms such as acidity have suffered a form of “rupture”, especially in the case of the modern Lewis definition of acids. Chang also complains that the degree of acidity of a Lewis acid cannot be measured using a pH meter and seems to regard this as a serious problem. The present paper examines some of these views, especially what Chang claims to be a rupture in the definition of acidity. It is suggested that there has been no such rupture but a genuine generalization, on moving from the Brønsted-Lowry theory to the Lewis theory of acidity. It will be shown how the quantification and measurement of Lewis acidity can easily be realized through the use of equilibrium theory and the use of stability constants.
Robin Hendry has presented an account of two equally valid ways of understanding the nature of chemical bonding, consisting of what the terms the structural and the energetic views respectively. In ...response, Weisberg has issued a “challenge to the structural view”, thus implying that the energetic view is the more correct of the two conceptions. In doing so Weisberg identifies the delocalization of electrons as the one robust feature that underlies the increasingly accurate quantum mechanical calculations starting with the Heitler-London method and moving on to such approaches as the valence bond and molecular orbital theories of chemical bonding. The present article provides a critical evaluation of Weisberg’s article and concludes that he fails to characterize the nature of chemical bonding in several respects. I claim that Hendry’s structural and energetic views remain as equally viable ways of understanding chemical bonding. Whereas the structural view is more appropriate for chemists, the energetic view is preferable to physicists. Neither view is more correct unless one subscribes to the naively reductionist view of considering that the more physical energetic view is the more correct one.
In praise of triads Scerri, Eric R.
Foundations of chemistry,
07/2022, Letnik:
24, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The article begins with a response to a recent contribution by Jensen, in which he has criticized several aspects of the use of triads of elements, including Döbereiner’s original introduction of the ...concept and the modern use of atomic number triads by some authors including myself. Such triads are groups of three elements, one of which has approximately the average atomic weight of the other two elements, as well as having intermediate chemical reactivity. I also examine Jensen’s attempted reconstruction Mendeleev’s use of triads in predicting the atomic weights of three hitherto unknown elements, that were subsequently named gallium, germanium and scandium. The present article then considers the use of atomic number triads, in conjunction with the phenomenon of first member anomaly, in order to offer support for Janet’s left-step periodic table, in which helium is relocated into group 2 of the table. Such a table features triads in which the 2nd and third elements of each group, without fail, fall into periods of equal length, a feature that is absent in the conventional 18-column or the conventional 32-column table. The dual sense of the term element, which is the source of much discussion in the philosophy of chemistry, is alluded to in further support of such a relocation of helium that may at first appear to contradict chemical intuition.
PDF
