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 methods to create new elements at the end of the Periodic Table point to the importance of methodological development complementing conceptual advances. I propose to frame the crossover from physics to chemistry not as a loss of accuracy and precision but as an increased application of vague concepts such as similarity which permit classification. This approach provides epistemic flexibility to adapt to scientific anomalies and the continued growth of chemical compound space and rejects the Procrustean philosophy of reductionist physics. Furthermore, it establishes chemistry with its explanatory and operational autonomy epitomized by the periodic system of elements as a gateway to other experimental sciences. (shrink)

Periodic tables (PTs) are the ‘ultimate paper tools’ of general and inorganic chemistry. There are three fields of open questions concerning the relation between PTs and physics: (i) the relation between the chemical facts and the concept of a periodic system (PS) of chemical elements (CEs) as represented by PTs; (ii) the internal structure of the PS; (iii)␣The relation between the PS and atomistic quantum chemistry. The main open questions refer to (i). The fuzziness of (...) the concepts of chemical properties and of chemical similarities of the CE and their compounds guarantees the autonomy of chemistry. We distinguish between CEs, Elemental Stuffs and Elemental Atoms. We comment on the basic properties of the basic elements. Concerning (ii), two sharp physical numbers (nuclear charge and number of valence electrons) and two coarse fuzzy ranges (ranges of energies and of spatial extensions of the atomic orbitals, AOs) characterize the atoms of the CEs and determine the two-dimensional structure of the PS. Concerning (iii), some relevant ‘facts’ about and from quantum chemistry are reviewed and compared with common ‘textbook facts’. What counts in chemistry is the whole set of nondiffuse orbitals in low-energy average configurations of chemically bonded atoms. Decisive for the periodicity are the energy gaps between the core and valence shells. Diffuse Rydberg orbitals and minute spin–orbit splittings are important in spectroscopy and for philosophers, but less so in chemical science and for the PS. (shrink)

Though complex networks have been widely applied in the research of chemistry, there is hardly any introduction about the establishment of networks using chemical bonds. In this paper, we consider chemical elements as a system linked by chemical bonds and create the undirected chemical bond network by abstracting nodes from elements and undirected edges from bonds. Connectivity, heterogeneity, small world and disassortativity of this network show the macro structural rationality of this system. The degree (...) and k-order neighbors of an element, which represent the micro topology of this network, can be used to measure its chemical reactivity and detect how many kinds of compounds it can form. The similarity between two elements is measured by the Jaccard index and the VOS mapping technique, results of which are similar to well-known similarities between elements shown by the periodic table. The establishment and topological analysis of this network provide another way to understand and study elements and bonds, and more chemical properties of elements and bonds can be studied by complex networks. (shrink)

A 4-dimensional periodic table of chemical elements is presented. The 120 elements in the n = 8 system are located on vertices of a 4D-cubic lattice and specified by Cartesian coordinates based on the four quantum numbers. Each quantum number is represented by a vector along a different spatial direction in 4D Euclidean space. The 4D PT has a fixed topology governed by Euler–Poincare-type equation and the chemical elements have a fixed connectivity with (...) neighboring elements within the 4D PT. Various geometric transformations by rotations and elongations of vectors enable morphing of one PT to another in a continuum while preserving the 4D topology. The 4D structure exhibits principles of complementarity and zero-cyclic sum in chemical elements. Complementarity enables the extension to n = 9 elements and beyond. The 4D PT of elements extends to isotopes and also to molecules and compounds with the same underlying principles. (shrink)

Helium and neon, the two lightest noble gases, have been traditionally positioned by IUPAC in the Group 18 of the Periodic Table of Elements, together with argon, and other unreactive or moderately reactive gaseous elements (krypton, xenon, radon), and oganesson. In this account we revive the old discussion on the possible placement of helium in the Group 2, while preserving the position of neon in Group 18. We provide quantum-chemical arguments for such scenario—as well as (...) other qualitative and quantitative arguments—and we describe previous suggestions in the literature which support it or put it into question. To this author’s own taste, He should be placed in Group 2. (shrink)

A large variety of periodic tables of the chemical elements have been proposed. It was Mendeleev who proposed a periodic table based on the extensive periodic law and predicted a number of unknown elements at that time. The periodic table currently used worldwide is of a long form pioneered by Werner in 1905. As the first topic, we describe the work of Pfeiffer, who refined Werner’s work and rearranged the rare-earth (...) class='Hi'>elements in a separate table below the main table for convenience. Today’s widely used periodic table essentially inherits Pfeiffer’s arrangements. Although long-form tables more precisely represent electron orbitals around a nucleus, they lose some of the features of Mendeleev’s short-form table to express similarities of chemical properties of elements when forming compounds. As the second topic, we compare various three-dimensional helical periodic tables that resolve some of the shortcomings of the long-form periodic tables in this respect. In particular, we explain how the 3D periodic table “Elementouch”, which combines the s- and p-blocks into one tube, can recover features of Mendeleev’s periodic law. Finally we introduce a topic on the recently proposed nuclear periodic table based on the proton magic numbers. Here, the nuclear shell structure leads to a new arrangement of the elements with the proton magic-number nuclei treated like noble-gas atoms. We show that the resulting alignments of the elements in both the atomic and nuclear periodic tables are common over about two thirds of the tables because of a fortuitous coincidence in their magic numbers. (shrink)

At the heart of chemistry lies the periodic system of chemical elements. Despite being the cornerstone of modern chemistry, the overall structure of the periodic system has never been fully understood from an atomic physics point of view. Group-theoretical models have been proposed instead, but they suffer from several limitations. Among others, the identification of the correct symmetry group and its decomposition into subgroups has remained a problem to this day. In an effort to deepen our (...) limited understanding of the periodic law, we have extended the traditional Lie algebraic framework to account for the peculiar degeneracy structure of the periodic system. Starting from the four-dimensional hidden symmetry and accidental degeneracy of the hydrogen atom, as first revealed by Fock in 1935, our research has mainly focussed on the way this SO(4) symmetry of the Coulomb potential gets broken in the periodic system as a consequence of the transformation of the hydrogenic (n, l) filling order to the Madelung (n+l, n) order due to electronic repulsions, relativistic effects and spin-orbit couplings. In this PhD dissertation, a new left-step format of the periodic table is first proposed on the basis of the Madelung rule. Following the particle physics tradition, the chemical elements are then considered as various states of some 'atomic matter', which is described by a non-compact spectrum-generating dynamical Lie group. The chemical elements are shown to form a basis for a single infinite-dimensional degeneracy space of the SO(4,2) ⊗ SU(2) group. An explanation for the period doubling is then proposed in terms of a particular symmetry breaking of the SO(4,2) group to the anti de Sitter SO(3,2) group. The Madelung rule is rationalised on the basis of nonlinear Lie algebras which reflect the screening of the Coulomb hole. This opens new perspectives for a symmetry-based understanding of how the periodic law emerges from its quantum mechanical foundations, and holds the future promise of complementing our current phenomenological approach by a direct atomic physics approach. (shrink)

The periodic table of the elements is one of the most powerful icons in science: a single document that captures the essence of chemistry in an elegant pattern. Indeed, nothing quite like it exists in biology or physics, or any other branch of science, for that matter. One sees periodic tables everywhere: in industrial labs, workshops, academic labs, and of course, lecture halls. It is sometimes said that chemistry has no deep ideas, unlike physics, which can (...) boast quantum mechanics and relativity, and biology, which has produced the theory of evolution. This view is mistaken, however, since there are in fact two big ideas in chemistry. They are chemical periodicity and chemical bonding, and they are deeply interconnected. The observation that certain elements prefer to combine with specific kinds of elements prompted early chemists to classify the elements in tables of chemical affinity. Later these tables would lead, somewhat indirectly, to the discovery of the periodic system, perhaps the biggest idea in the whole of chemistry. Indeed, periodic tables arose partly through the attempts by Dimitri Mendeleev and numerous others to make sense of the way in which particular elements enter into chemical bonding. (shrink)

Some recent work in mathematical chemistry is discussed. It is claimed that quantum mechanics does not provide a conclusive means of classifying certain elements like hydrogen and helium into their appropriate groups. An alternative approach using atomic number triads is proposed and the validity of this approach is defended in the light of some predictions made via an information theoretic approach that suggests a connection between nuclear structure and electronic structure of atoms.

The thesis is: the “periodic table” of “dark matter” is equivalent to the standard periodic table of the visible matter being entangled. Thus, it is to consist of all possible entangled states of the atoms of chemical elements as quantum systems. In other words, an atom of any chemical element and as a quantum system, i.e. as a wave function, should be represented as a non-orthogonal in general (i.e. entangled) subspace of the separable (...) complex Hilbert space relevant to the system to which the atom at issue is related as a true part of it. The paper follows previous publications of mine stating that “dark matter” and “dark energy” are projections of arbitrarily entangled states on the cognitive “screen” of Einstein’s “Mach’s principle” in general relativity postulating that gravitational field can be generated only by mass or energy. (shrink)

We briefly describe in this paper the passage from Mendeleev’s chemistry (1869) to atomic physics (in the 1900’s), nuclear physics (in 1932) 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 the application of the group SO(4,2)⊗SU(2) to the periodic table of (...) chemical elements. It is shown how the Madelung rule of the atomic shell model can be used to set up a periodic table that can be further rationalized via the group SO(4,2)⊗SU(2) and some of its sub-groups. Qualitative results are obtained from this nonstandard table. (shrink)

Among the subjects that attract historians of chemistry and philosophers of chemistry alike are the chemical elements and their classification within the periodic system. In 2007, Eric Scerri, a distinguished philosopher of the chemical sciences, published The Periodic Table (Oxford University Press), a comprehensive and critical account of the subject. He describes the present work as “a follow-up book,” and a few of the chapters are indeed condensed versions of chapters appearing in the 2007 (...) book. Nonetheless, A Tale of 7 Elements has a different scope and also a different intended audience. It is a story of seven little-known elements, some of which—such as promethium, francium and astatine—are extremely rare and with almost no applications. While Scerri’s 2007 book was in the more traditional academic genre, this one appeals to an audience much wider than the limited community of historians and philosophers of science. It is a brave and largely successful attempt to bridge the infa .. (shrink)

Electronegativity, described by Linus Pauling described as “The power of an atom in a molecule to attract electrons to itself” (Pauling in The nature of the chemical bond, 3rd edn, Cornell University Press, Ithaca, p 88, 1960), is used to predict bond polarity. There are dozens of methods for empirically quantifying electronegativity including: the original thermochemical technique (Pauling in J Am Chem Soc 54:3570–3582, 1932), numerical averaging of the ionisation potential and electron affinity (Mulliken in J Chem Phys 2:782–784, (...) 1934), effective nuclear charge and covalent radius analysis (Sanderson in J Chem Phys 23:2467, 1955) and the averaged successive ionisation energies of an element’s valence electrons (Martynov and Batsanov in Zhurnal Neorganicheskoi Khimii 5:3171–3175, 1980), etc. Indeed, there are such strong correlations between numerous atomic parameters—physical and chemical—that the term “electronegativity” integrates them into a single dimensionless number between 0.78 and 4.00 that can be used to predict/describe/model much of an element’s physical character and chemical behaviour. The design of the common and popular medium form of the periodic table is in large part determined by four quantum numbers and four associated rules. However, adding electronegativity completes the construction so that it displays the multi-parameter periodic law operating in two dimensions, down the groups and across the periods, with minimal ambiguity. (shrink)

This article considers two important traditions concerning the chemical elements. The first is the meaning of the term “element” including the distinctions between element as basic substance, as simple substance and as combined simple substance. In addition to briefly tracing the historical development of these distinctions, I make comments on the recent attempts to clarify the fundamental notion of element as basic substance for which I believe the term “element” is best reserved. This discussion has focused on the (...) writings of Fritz Paneth which are here analyzed from a new perspective. The other tradition concerns the reduction of chemistry to quantum mechanics and an understanding of chemical elements through their microscopic components such as protons, neutrons and electrons. I claim that the use of electronic configurations has still not yet settled the question of the placement of several elements and discuss an alternative criterion based on maximizing triads of elements. I also point out another possible limitation to the reductive approach, namely the failure, up to now, to obtain a derivation of the Madelung rule. Mention is made of some recent similarity studies which could be used to clarify the nature of ‘elements’. Although it has been suggested that the notion of element as basic substance should be considered in terms of fundamental particles like protons and electrons, I resist this move and conclude that the quantum mechanical tradition has not had much impact on the question of what is an element which remains an essentially philosophical issue. (shrink)

In this essay, we aim to provide an overview of the periodic table’s origins and history, and of the elements which conspired to make it chemistry’s most recognisable icon. We pay attention to Mendeleev’s role in the development of a system for organising the elements and chemical knowledge while facilitating the teaching of chemistry. We look at how the reception of the table in different chemical communities was dependent on the local scientific, cultural (...) and political context, but argue that its eventual universal acceptance is due to its unique ability to accommodate possessed knowledge while enabling novel predictions. Furthermore, we argue that its capacity to unify apparently disconnected phenomena under a simple framework facilitates our understanding of periodicity, making the table an icon of aesthetic value, and an object of philosophical inquiry. Finally, we briefly explore the table’s iconicity throughout its representations in pop art and science fiction. (shrink)

Between 1869 and 1871, D. I. Mendeleev, a teacher at the University at St Petersburg published a textbook of general chemistry intended for his students. The title, Principles of Chemistry was typical for the time: it meant that chemistry was no longer an inquiry on the ultimate principles of matter but had become a science firmly established on a few principles derived from experiment.

This is a periodic table explicitly for chemists rather than physicists. It is derived from Newlands’ columns. It solves many problems such as the positions of hydrogen, helium, beryllium, zinc and the lanthanoids but all within a succinct format.

Within contemporary personality psychology there is widespread consensus that, at long last, the basic elements of "the" human personality have been empirically discovered, and that the systematic search for the underlying causes and consequences of personality differences can be pursued on this basis. The putatively basic trait dimensions are neuroticism, extraversion, openness, agreeableness, and conscientiousness, and are referred to collectively as "the Big Five." In the present article, this perspective on the psychology of personality is examined critically and found (...) wanting. It is argued that neither the "Big Five" framework in particular nor trait "psychology" more generally is adequate as the basis for a scientific psychology of the human person. 2012 APA, all rights reserved). (shrink)

After 150 years of scientific developments, the periodic system of chemical elements is still an icon of modern science. Its resilience is striking. The icon used today by scientists and teachers is in fact the outcome of many rearrangements and reinterpretations by the scientific community during that period. This success is often explained as a result of the underlying atomic structure, discovered in the first decades of the 20th century, an explanation that completely neglects the fine structure (...) of the process of ongoing renegotiation and successive stabilizations. How did indeed contemporary scientists navigate in times of reinterpretation? The physicist Lise Meitner and the chemist Ida Noddack were, in different ways, involved in discoveries and interpretations of the periodic system. In 1934, as part of the celebration of the centenary of Dmitri Mendeleev's birth, they each published an article on the system: Meitner in Die Naturwissenschaften, and Noddack in Angewandte Chemie. These two articles, written from the perspectives of a nuclear physicist and a chemist experienced in searching for undiscovered elements, respectively, constitute excellent sources for understanding what new discoveries and insights meant for the meaning and value of the periodic system at the very beginning of the nuclear age in science. Through an analysis of the two contributions, we will argue that resilience is the foremost value of the periodic system. We will also discuss what this value means for the future of the periodic system and its representations. (shrink)

The periodic table represents and organizes all known chemical elements on the basis of their properties. While the importance of this table in chemistry is uncontroversial, the role that it plays in scientific reasoning remains heavily disputed. Many philosophers deny the explanatory role of the table and insist that it is “merely” classificatory (Shapere, in F. Suppe (Ed.) The structure of scientific theories, University of Illinois Press, Illinois, 1977; Scerri in Erkenntnis 47:229–243, 1997). In (...) particular, it has been claimed that the table does not figure in causal explanation because it “does not reveal causal structure” (Woody in Science after the practice turn in the philosophy, history, and social studies of science, Routledge Taylor & Francis Group, New York, 2014). This paper provides an analysis of what it means to say that a scientific figure reveals causal structure and it argues that the modern periodic table does just this. It also clarifies why these “merely” classificatory claims have seemed so compelling–this is because these claims often focus on the earliest periodic tables, which lack the causal structure present in modern versions. (shrink)

The history of the classification of chemical elements is reviewed from the point of view of a bibliophile. The influence that relevant books had on the development of the periodic table and, conversely, how it was incorporated into textbooks, treatises and literary works, with an emphasis on the Spanish bibliography are analyzed in this paper. The reader will also find unexpected connections of the periodic table with the Bible or the architect Buckminster Fuller.

Measurement theory in (Hand in The world through quantification. Oxford University Press, 2004; Suppes and Zinnes in Basic measurement theory. Psychology Series, 1962) is concerned with the assignment of number to objects of phenomena. Representational aspect of measurement is the extent to which the assigned numbers and arithmetics truthfully represent the underlying objects and their relations, and is characteristic to natural sciences; pragmatic aspect is the extent to which the assigned numbers serve purposes other than representing the underlying phenomena, and (...) is characteristic to social sciences (Hand in The world through quantification. Oxford University Press, 2004). Here I criticise this distinction of representational and pragmatic measurements on the basis of the earlier history of the periodic system of chemical elements, viewed in terms of a practice based philosophy of science by Rein Vihalemm. I argue that the periodic system, although a natural scientific system interpretable as a measurement system, has considerable, in Hand’s terms pragmatic, aspects in it. Those aspects include: tampering with the material measurement results for the theoretical ideal of systematicity; adopting metaphysical assumptions that cannot be experimentally proven, like individuality of elements and atomicity; theoretical construction of the abstract entity—element—as the reference of the measurement system amenable to mathematically elegant ordering. Contrary to Suppes and Zinnes (Basic measurement theory. Psychology Series, 1962) I also argue for the dependence of the assigned numerical system on the material-procedural base of the measurement. (shrink)

This chapter gives an overview of the evolution of the position of the rare-earth elements in the periodic system, from Mendeleev’s time to the present. Three fundamentally different accommodation methodologies have been proposed over the years. Mendeleev considered the rare-earth elements as homologues of the other elements. Other chemists looked upon the rare earths as forming a special intraperiodic group and therefore clustered the rare-earth elements in one of the groups of the periodic (...) class='Hi'>table. Still others adhered to the intergroup accommodation of the rare earths, according to which the rare-earth elements do not show any relationship with the other elements, so that they had to be placed within the periodic table as a separate family of elements. The intergroup accommodation became the preferred one in the twentieth century. The advantages and disadvantages of the different representations of the modern periodic table are discussed. (shrink)

Historians and philosophers of science generally conceptualize scientific progress to be dichotomous, viz., experimental observations lead to scientific laws, which later facilitate the elaboration of explanatory theories. There is considerable controversy in the literature with respect to Mendeleev’s contribution to the origin, nature, and development of the periodic table. The objectives of this study are to explore and reconstruct: a) periodicity in the periodic table as a function of atomic theory; b) role of predictions in scientific (...) theories and its implications for the periodic table; and c) Mendeleev’s contribution: theory or an empirical law? The reconstruction shows that despite Mendeleev’s own ambivalence, periodicity of properties of chemical elements in the periodic table can be attributed to the atomic theory. It is argued that based on the Lakatosian framework, predictions play an important role in the development of scientific theories. In this context, Mendeleev’s predictions played a crucial role in the development of the periodic table. Finally, it is concluded that Mendeleev’s contribution can be considered as an “interpretative” theory which became “explanatory” after the periodic table was based on atomic numbers.Author Keywords: Periodic table; Mendeleev’s contribution; Theory; Empirical law; Interpretative theory. (shrink)

Symmetry is at the heart of our understanding of matter. This book tells the fascinating story of the constituents of matter from a common symmetry perspective. The standard model of elementary particles and the periodic table of chemical elements have the common goal to bring order in the bewildering chaos of the constituents of matter. Their success relies on the presence of fundamental symmetries in their core. -/- The purpose of Shattered Symmetry is to share the (...) admiration for the power and the beauty of these symmetries. The reader is taken on a journey from the basic geometric symmetry group of a circle to the sublime dynamic symmetries that govern the motions of the particles. Along the way the theory of symmetry groups is gradually introduced with special emphasis on its use as a classification tool and its graphical representations. This is applied to the unitary symmetry of the eightfold way of quarks, and to the four-dimensional symmetry of the hydrogen atom. The final challenge is to open up the structure of Mendeleev's table which goes beyond the symmetry of the hydrogen atom. Breaking this symmetry to accommodate the multi-electron atoms requires us to leave the common ground of linear algebras and explore the potential of non-linearity. (shrink)

The debate about the relative epistemic weights carried in favour of a theory by predictions of new phenomena as opposed to accommodations of already known phenomena has a long history. We readdress the issue through a detailed re-examination of a particular historical case that has often been discussed in connection with it—that of Mendeleev and the prediction by his periodic law of the three ‘new’ elements, gallium, scandium and germanium. We find little support for the standard story that (...) these predictive successes were outstandingly important in the success of Mendeleev's scheme. Accommodations played an equal role—notably that of argon, the first of the ‘noble gases’ to be discovered; and the methodological situation in this chemical example turns out to be in interesting ways different from that in other cases—invariably from physics—that have been discussed in this connection. The historical episode when accurately analysed provides support for a different account of the relative weight of prediction and accommodation—one that is further articulated here. (shrink)

In this commentary to Leal (2013), we argue that the memorization of the names and symbols of the chemical elements is necessary in the study of that topic because this task is the key for the later understanding of the Periodic Table. We can make the memorization task in an enjoyable, but effective way, using some educational games in chemistry class. Some recent puzzles, card games, mnemonics rules or games based on drawings to learn the (...) class='Hi'>chemical elements are addressed in this paper. (shrink)

This work utilizes examples from chemical sciences to present fundamentals of dialectics and synergetics. The laws of dialectics remain appropriate at the level of atoms, at the level of molecules, at the level of the reactions, and at the level of ideas. The law of the unity and conflict of opposites is seen, for instance, in the relationships between the ionization energy and electron affinity of atoms, between the forward and back reactions, as well as in the differentiation and (...) integration between the various areas of chemistry. The law of the passage of quantitative changes into qualitative changes describes the transformation properties of the compounds when the number and arrangement of atoms in the molecule undergoes changes. According to this law, the development is accompanied by breaks and jumps. This paper suggests equations for the description of these relationships. The law of the negation of the negation is manifested in the Periodic Law, in the evolution of ideas about the mutual transformation of chemical elements, in the development the concept of triads of elements, etc. Small changes in the conventional Periodic Table on the basis of previously rejected versions allow reflecting secondary and additional periodicity. Synergetics, similarly to dialectics, is dedicated to the studies of general laws of evolution. Synergetics includes highly advanced and specified ideas of dialectics. The cornerstone of synergetics is the principles of self-organization and nonlinearity. Mathematical development of these concepts was substantially facilitated by considering oscillating chemical reactions as an example. These reactions are quite complex and therefore provide adequate models for self-organization. Oscillations may exist only upon execution of specific thermodynamic, mathematical, and chemical conditions. Mechanisms of several oscillatory reactions are briefly reviewed. The construction of novel biomimetic or smart materials based on oscillating reactions is described. (shrink)

The debate about the relative epistemic weights carried in favour of a theory by predictions of new phenomena as opposed to accommodations of already known phenomena has a long history. We readdress the issue through a detailed re-examination of a particular historical case that has often been discussed in connection with it-that of Mendeleev and the prediction by his periodic law of the three 'new' elements, gallium, scandium and germanium. We find little support for the standard story that (...) these predictive successes were outstandingly important in the success of Mendeleev's scheme. Accommodations played an equal role-notably that of argon, the first of the 'noble gases' to be discovered; and the methodological situation in this chemical example turns out to be in interesting ways different from that in other cases-invariably from physics-that have been discussed in this connection. The historical episode when accurately analysed provides support for a different account of the relative weight of prediction and accommodation-one that is further articulated here. (shrink)

Traditionally the study of chemical elements has been limited to well-known concepts like the periodic properties and chemical families. However, current information shows a new and rich language that allows us to observe relations in the elements that are not limited to their positions in the table. These relations are evident when reactions are represented through networks, as in the case of similar reactivity of organic compounds sharing functional groups. For the past two decades, (...) it has been argued that network reactions may be considered the core of chemistry. This network, which constitutes the basic set of chemical knowledge, provides the basis for classification and delivers routes to obtain new and known substances. In order to provide an example, we constructed and analyzed a network of chemical elements from the formation of stoichiometric binary compounds, providing to the chemistry, a formal structure of extracting the chemical knowledge. Thus, we explored all possible presence of relationships among elements. Concepts like degree centrality and centralization, the relationships among metals, semimetal and nonmetal classes, blocks, and chemical families were analyzed. We observed that the network structure had a small core set of elements of high reactivity and also a peripheral set of elements of low reactivity. The classes, blocks and families show the following increasing order of reactivity: nonmetals > semimetals > metals; p > s > d > f; and families: boron, carbon, pnictogens, chalcogens, halogens, lanthanoids > other families. This example shows, from the network perspective, that the elements and their classifications exhibit properties such as the reactivity, order, and similarity. (shrink)

The recent exchange on the quantum justification of the Periodic System of the Elements in this Journal between Scerri [Foundations of Chemistry 6: 93–116, 2004] and Friedrich [Foundations of Chemistry 6: 117–132, 2004] is supplemented by some methodological comments.

Sometimes the right book finds you at the right time, and it shifts your perception of a familiar subject just a little, just enough to make a difference. It reminds you of something important you haven’t thought of in a while, or it shows you a new way of looking at and interacting with the world. Last winter, for me, that book was The Disappearing Spoon, by Sam Kean. I heard a very fuzzy description of the book at a holiday (...) party, something about the periodic table and political history. As someone eternally interested in chemistry and its impact on society at large, I was intrigued. (shrink)

From Mendeleev’s time on, the Periodic Table has been an attempt to exhaust all the chemical possibilities of the elements and their interactions, whether these elements are known as actual or are not known yet as such. These latter elements are called “eka-elements” and there are still some of them in the current state of the Table. There is no guarantee that they will be eventually discovered, synthesized, or isolated as actual. As (...) long as the actual existence of eka-elements is predicted, they cannot be considered as actual but only as purely possible. Given that eka-elements are chemical pure possibilities, a possibilist approach, entitled “panenmentalism,” can gain support as well as an important implication. (shrink)

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. (shrink)

Sam Kean: The disappearing spoon: and other true tales of madness, love, and the history of the world from the periodic table of the elements Content Type Journal Article Pages 77-77 DOI 10.1007/s10698-010-9101-x Authors Michael Laing, School of Pure and Applied Chemistry, University of KwaZulu-Natal, Durban, 4041 South Africa Journal Foundations of Chemistry Online ISSN 1572-8463 Print ISSN 1386-4238 Journal Volume Volume 13 Journal Issue Volume 13, Number 1.

Many different arguments have been put forward in order to assign the best place for a given element within Mendeleev's Table: its spectroscopy, its chemical activity, the crystalline structure of its solid state, etc. We here propose another criterion; the nature of the few body corrections to the pairwise additive energy. This argument is used here to address a question often brought forward by Eric Scerri in Foundations of Chemistry, namely the rightful place of helium; either above the (...) column of the alkaline earths (beryllium, etc.) or rather above the noble gas elements. (shrink)

In case of that human civilization was viewed as an integrated organism, the Periodic Table of the Civilizations (PTOC in short) has been formulated and recommended based on the development level and periodicity of core elements of human civilization. It divides the frontier process of the human civilization from the birth of humankind to the end of twenty-first century into 4 periods and 16 stages, and in which four periods include that of primitive culture, agricultural civilization, industrial (...) civilization and knowledge civilization orderly, and each period includes four stages, that is, start, developing, maturing and transition stages sequentially. There are three approaches for the arrangements of the PTOC, that is, simple, vertical and horizontal tables. The big period of earth civilization refers to that from the primitive culture to the knowledge civilization, and then big period of space civilization will begin with the astronautic civilization. The first modernization witnesses the great changes and transformation from the traditional agricultural to the modern industrial civilization, and then second modernization from the modern industrial to the higher modern knowledge civilization. The periodic table, coordinate system and roadmap of human civilization and world modernization have been formulated to describe the relationship between them. (shrink)

The seventh sign in Charles Peirce’s well-known 10-sign taxonomy of the 1903 Syllabus has received relatively little attention compared to many other types of sign that he described. It is the sign type of “Dicent Indexical Legisigns”, a result of the combinatory strategy of the 3x3 elementary sign aspects defined by the three basic sign trichotomies of Qualisign-Sinsign-Legisign, Icon-Index-Symbol and Rheme-Dicisign-Argument, a new strategy developed by Peirce in that famous text. It is well known how such aspects do not combine (...) freely, hence not resulting in 3 × 3 × 3 = 27 sign types, but only in 10 sign types, due to the application of the rule aptly summarized by Bellucci as “a certain combination... (shrink)

Demarcation of elements for two subsets appears to be the most fundamental approach to their classification. If one draws a vertical straight line through the middle of each block of elements in the Periodic table, all the elements are divided into two subsets: “early” and “later”. For example, in the d-block, the early ones are Sc–Mn, and the late ones, respectively, are Fe–Zn. Later elements partially repeat the properties of the early ones, and this (...) is defined as the internal periodicity. Another criterion for dividing the elements into two subsets is the evenness and oddness of the sum of n + l, where n is the principal quantum number, and l is the orbital quantum number for the outer electron subshells. Properties of the odd elements are closer to each other than to properties of even elements, and vice versa. This regularity is manifested as the secondary periodicity. The history of concepts, which considered the existence of subsets as well as of inner and secondary periodicities, is discussed. The features of the electronic structure, which underlie the existence of subsets, are considered. The existence of subsets was depicted earlier by dividing the periodic table into two tables or by applying a mirror-symmetric table. Small changes are proposed in the conventional Periodic table, allowing to reflect the existence of the considered subsets. (shrink)

Demarcation of elements for two subsets appears to be the most fundamental approach to their classification. If one draws a vertical straight line through the middle of each block of elements in the Periodic table, all the elements are divided into two subsets: “early” and “later”. For example, in the d-block, the early ones are Sc–Mn, and the late ones, respectively, are Fe–Zn. Later elements partially repeat the properties of the early ones, and this (...) is defined as the internal periodicity. Another criterion for dividing the elements into two subsets is the evenness and oddness of the sum of n + l, where n is the principal quantum number, and l is the orbital quantum number for the outer electron subshells. Properties of the odd elements are closer to each other than to properties of even elements, and vice versa. This regularity is manifested as the secondary periodicity. The history of concepts, which considered the existence of subsets as well as of inner and secondary periodicities, is discussed. The features of the electronic structure, which underlie the existence of subsets, are considered. The existence of subsets was depicted earlier by dividing the periodic table into two tables or by applying a mirror-symmetric table. Small changes are proposed in the conventional Periodic table, allowing to reflect the existence of the considered subsets. (shrink)

No one knows yet how to organize, in a simple yet predictive form, the knowledge concerning the anatomical, biophysical, and molecular properties of neurons that are accumulating in thousands of publications every year. The situation is not dissimilar to the state of Chemistry prior to Mendeleev's tabulation of the elements. We propose that the patterns of presence or absence of axons and dendrites within known anatomical parcels may serve as the key principle to define neuron types. Just as the (...) positions of the elements in the periodic table indicate their potential to combine into molecules, axonal and dendritic distributions provide the blueprint for network connectivity. Furthermore, among the features commonly employed to describe neurons, morphology is considerably robust to experimental conditions. At the same time, this core classification scheme is suitable for aggregating biochemical, physiological, and synaptic information. (shrink)

A numerical classification was performed on 69 elements with 54 chemicaland physicochemical properties. The elements fell into clusters in closeaccord with the electron shell s-, p- andd-blocks. The f-block elements were not included forlack of sufficiently complete data. The successive periods ofs- and p-block elements appeared in an ovalconfiguration, with d-block elements lying to one side. Morethan three axes were required to give good representation of thevariation, although the interpretation of the higher axes is difficult.Only (...) 15 properties were scorable for the noble gases, but despite thepaucity of properties reflecting chemical reactivity, analysis of the 69elements on these properties still showed the major features seen fromthe full set. (shrink)

To this day, a hundred and fifty years after Mendeleev's discovery, the overal structure of the periodic system remains unaccounted for in quantum-mechanical terms. Given this dire situation, a handful of scientists in the 1970s embarked on a quest for the symmetries that lie hidden in the periodic table. Their goal was to explain the table's structure in group-theoretical terms. We argue that this symmetry program required an important paradigm shift in the understanding of the nature (...) of chemical elements. The idea, in essence, consisted of treating the chemical elements, not as particles, but as states of a superparticle. We show that the inspiration for this came from elementary particle physics, and in particular from Heisenberg's suggestion to treat the proton and neutron as different states of the nucleon. We provide a careful study of Heisenberg's last paper on the nature of elementary particles, and explain why the Democritean picture of matter no longer applied in modern physics and a Platonic symmetry-based picture was called for instead. We show how Heisenberg's Platonic philosophy came to dominate the field of elementary particle physics, and how it found its culmination point in Gell-Mann's classification of the hadrons in the eightfold way. We argue that it was the success of Heisenberg's approach in elementary particle physics that sparked the group-theoretical approach to the periodic table. We explain how it was applied to the set of chemical elements via a critical examination of the work of the Russian mathematician Abram Ilyich Fet the Turkish-American physicist Asim Orhan Barut, before giving some final reflections. (shrink)

The periodic table may be seen as the most successful example of inquiry in the history of science, both in terms of practical application and theoretic understanding. As such, it serves as a model for truth as it emerges from inquiry. This paper offers a sketch of a central moment in the history of chemistry that illustrates an intuitive metamathematical construction, a model of emerging truth. The MET, reflecting the structure the surrounds the periodic table, attempts (...) to capture the salient epistemological elements that warrant truth claims based on sets of models that are progressive in light of both empirical and theoretical advance seen over time. (shrink)