Chemical atomism

November 9,1994 at 4 39 pm, the first atom of the heaviest chemical atom with atomic number 110 was detected at the Gesellschaft fur Schwerionenforschung (GSI) in Darmstadt, in Germany. For the last ten years, this element has been the subject of an intense search by many laboratories world-wide. 

The dawn of the nineteenth century saw a drastic shift from the dominance of French chemistry to first English-, and, later, German-influenced chemistry. Lavoisier s dualistic views of chemical composition and his explanation of combustion and acidity were landmarks but hardly made chemistry an exact science. Chemistry remained in the nineteenth century basically qualitative in its nature. Despite the Newtonian dream of quantifying the forces of attraction between chemical substances and compiling a table of chemical affinity, no quantitative generalization emerged. It was Dalton s chemical atomic theory and the laws of chemical combination explained by it that made chemistry an exact science. 

The purity of commercial tin is under strict control at the smelters. Photometric, chemical, atomic absorption, fluorimetric, and spectrographic methods are available for the determination of impurities (17). 

Let us do a little bookkeeping with the exact masses of these nuclei. Actually we will simplify a bit and use the exact masses of the atoms. This will make no difference. The masses of the atoms differ from the nuclear masses by the masses of the number of electrons in each atom. We have shown that electrons are conserved in nuclear changes. Exact masses of atoms (that is, exact masses of each isotopic species and not the chemical atomic weights shown on the inside back cover) are readily available. For our hydrogen-helium reaction we have... 

There is an alternative to the notions of materialistic physicists, which may have more appeal for theosophists, and which should eventually prove reconcilable with the physicist s point of view. It is that the atoms seen by occultists are Archetypes. Can it be that they arose from thoughts in the Logoic Mind, densified in stages down to the etheric level, so that they are more fundamental than the chemical atoms we know in the dense physical world This notion would accord with the Story of Creation as told in theosophical literature, (ioo)... 

The statistical analysis required for real systems is no different in conception from the treatment of the hypothetical two-state system. The elementary particles from which the properties of macroscopic aggregates may be derived by mechanical simulation, could be chemical atoms or molecules, or they may be electrons and atomic nuclei. Depending on the nature of the particles their behaviour could best be described in terms of either classical or quantum mechanics. The statistical mechanics of classical and quantum systems may have many features in common, but equally pronounced differences exist. The two schemes are therefore discussed separately here, starting with the simpler classical sytems. 

Defects are often deliberately introduced into a solid in order to modify physical or chemical properties. However, defects do not occur in the balance of reactants expressed in traditional chemical equations, and so these important components are lost to the chemical accounting system that the equations represent. Fortunately, traditional chemical equations can be easily modified so as to include defect formation. The incorporation of defects into normal chemical equations allows a strict account of these important entities to be kept and at the same time facilitates the application of chemical thermodynamics to the system. In this sense it is possible to build up a defect chemistry in which the defects play a role analogous to that of the chemical atoms themselves. The Kroger-Vink notation allows this to be done provided the normal mles that apply to balanced chemical equations are preserved. 

During the course of the nineteenth century, organic chemists developed a complex and integrated theory of chemical identity and constitution that in eluded theories of chemical atoms and equivalents, radicals, substitution, types, and valence, eventually unified in the so-called structure theory of constitutional formulas. But by midcentury, there was some discontent among chemists about the limitations of the overall theoretical framework within which they were working. 

The Early Development of the Chemical Atomic Theory," HSPS 9 (1978) 225263, on 249250. 

On the atom, see Alan J. Rocke, Chemical Atomism in the Nineteenth Century From Dalton to Cannizzaro (Columbus Ohio State University Press, 1984) Mary Jo Nye, "The Nineteenth-Century Atomic Debates and the Dilemma of an Indifferent Hypothesis," SHPS 7 (1976) 245268 and Mi Gyung Kim,... 

In short, Dumas s chemical philosophy aimed at general abstract principles, which were identified with chemical atoms and chemical forces and it taught the history of chemistry as a guide to the progress of philosophical truth. 

On this, for the first half of the nineteenth century, see Rocke, Chemical Atomism and for the later period, M. J. Nye, ed., The Question of the Atom, and Molecular Reality A Perspective on the Scientific Work of Jean Perrin (London Macdonald, New York American Elsevier, 1972). 

Lewis appropriated Bohr s new atom to try to unify the physical and chemical atom. If the Bohr-Sommerfeld orbits are in fixed positions and orientations, "they may be used as the building stones of an atom which has an essentially static character." 17 Bohr s dynamic theory works for the chemist, Lewis wrote, if the "average" position of an electron in a Bohr-Sommerfeld orbit is taken to correspond to the fixed position of the electron in Lewis s static chemical model. The outermost shell of electrons constitutes the "valence" electrons, and the remaining electrons constitute the "kernel." 18... 

Chemical Atomism in the Nineteenth Century From Dalton to Cannizzaro. Columbus Ohio State University Press, 1984. 

The chemical analyses were done by a combination of wet chemical, atomic absorption (Hitachi Z-800) and ICP (JY-38 VHR) methods. The crystalline phase identification was carried out by XRD (Philips PW-1710 Cu K scanning electron microscopy (Cambridge, Stereoscan 400), thermal analysis (Netsch, Model STA 490), ESR... 

Shell. 1) A hollow metal projectile designed to be projected from a gun. It can contain an explosive, chemical, atomic or other charge. The term projectile is preferred for that kind of shell 2) A cartridge for artillery or small aims or a shotgun shell. The term cartridge is preferred for this kind of shell (Ref 40a,... 

Dalton presented his atomic theory in his bookyl New System of Chemical Philosophy, the first and crucial part of which was published in 1808. His pictures of atoms and molecules provide a unification of the micro-world and the macro-world of chemistry they show at once what we can observe (for example, hydrogen and oxygen combining to make water) and what we cannot the union of real, tangible atoms. Historian of chemistry William Brock says that Dalton s symbols encouraged people to acquire a faith in the reality of chemical atoms and enabled chemists to visualize relatively complex chemical reactions. .. Between them, Lavoisier and Dalton completed a revolution in the language of chemistry. ... 

The closer followers of Newton took up serious efforts to deal with the forces between the unseen particles, and though their efforts continued with great loyalty to the Newtonian ideal, none produced much of utility for chemistry. Nor did these efforts form a progressive step on which John Dalton later built his successful chemical atomic theory. Dalton owed little to anyone other than Newton himself, and here probably less than he thought. 

In offering my version of the origin of Daltons theory, I have generally followed the similarly titled account Leonard Nash, The Origin of Daltons Chemical Atomic Theory, Isis 47 (1956) 101-116, 2 Arnold Thackray, The Origin of Daltons Chemical Atomic Theory Daltonian Doubts Resolved, Isis 57 (1966) 35-55. 

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