The Chemical Atom

The idea that all matter is composed of minute atoms had first been suggested in ancient Greece, and Boyle had employed the concept of atomism in his mechanical philosophy. But atomism had as yet had little success in explaining the phenomena of chemistry. It was difficult to see how these minute particles, which were supposed to be the universal building blocks of nature, could provide an explanation for the chemical properties of the huge number of different materials known, a number that was continually increasing. 

Lavoisier s concept of an element provided the foundation for the new version of atomism which appeared in the early years of the nineteenth century. The new theory, known as the chemical atomic theory had as its central tenet that different elements have fundamentally different atoms. In consequence, repeated division of a piece of lead would ultimately yield the last atom of lead, and similarly repeated division of a piece of gold would yield the last atom of gold. If lead and gold were genuine elements, then the atoms of lead and the atoms of gold were different. This explained the different properties of lead and gold, and the transmutation so keenly sought by the alchemists became a theoretical impossibility. 

Working in the tradition of Black and Cavendish, Lavoisier had emphasised the importance of the use of the. balance in chemical investigations. The balance had been employed by assayers and mineral prospectors for hundreds of years, but in Lavoisier s time the precision balance was still a specialised piece of equipment. Black had used an apothecary s balance, but Cavendish and Lavoisier had much more accurate balances constructed to their own specifications. The age of quantitative chemistry had now truly arrived. 

The techniques of quantitative analysis were advanced significantly by the German, Martin Klaproth (1743-1817). He devoted much attention to sources of error and their elimination. He published all his experimental data, such as weights of 

Quantitative analysis was soon employed to verify the law of constant composition. It had for many years been assumed by most chemists that different samples of the same pure compound would have identical compositions. In 1799, the Frenchman Joseph Proust (1754-1826) analysed basic copper carbonate of natural occurrence (malachite) and the same compound prepared in the laboratory. Both samples gave the same analytical results. He demonstrated a similar constancy of composition in many other compounds, and he showed that several metals form more than one oxide and sulphide, each of definite composition. 

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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)... 

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. 

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

Cole, Jr, Theron. Dalton, Mixed Gases, and the Origin of the Chemical Atomic Theory. Ambix 25 (1978) 117-130. 

Chemical atomism was relatively uncontroversial, even though it was itself a hypothetical construct based upon assumptions concerning stoichiometric units that might vary between individual chemists. But physical atomism was controversial, and if ai rone attacked physical atomism, it was bound sometimes to impugn the legitimacy of the chemical atom, despite the latter s usefulness as an analytical stoichiometric category. 

Brodie s attempt to abolish the chemical atom, and thereby the physical atom, would not work. Nevertheless, Brodie persisted with his Calculus trying to incorporate carbon compounds into the system, but faihng to find a simple way of distinguishing between ordinary isomers (which have identical weights and therefore identical symbols), let alone stereochemical ones. He died in 1880 having failed to persuade chemists that his anti-atomistic stance was a sensible way forward now that organic chemists were able to picture molecular structures using atomic symbolism. 

The discovery of the atom of electricity led to a flimy of specrrlation about the arrangement of the electrons inside the chemical atom. Intact chemical atoms are electrically neutral, but Perrin observed that when the cathode rays are produced, positive ions are also created. The notion that atoms are a combination of positive and negative parts is one of the key insights of this period. But the number of electrons and the natirre of the positive part was still tmknown. 

The following values of isotopic atomic weights and abundances are obtained with a mass spectrometer. Compute the chemical atomic weights for the elements involved. The isotopic weights are in parentheses. 

While Lavoisier undoubtedly laid the foundations for the rapid rise of chemistry in the nineteenth century, his work was supported by that of other French chemists both before and after him.247 Without the Lavoisierian notion of the chemical element, it is unlikely that the chemical atomic theory and the laws of chemical combination would have been so widely accepted. However, a new perspective on the history of the concept of the chemical compound as the basis of modem chemistry suggests that it began long before Lavoisier and belongs to a different line of development involving the notion of chemical affinity .248-250... 

In the early years of the nineteenth century, the new chemistry began to bear fruit on both sides of the Channel,270 as well as in other countries, notably in Sweden. The chemical atomic theory proposed by Dalton and developed by Berzelius led to the formulation of the stoichiometric laws of chemical combination and the diligent search for accurate atomic weights. The important link between atoms and electrical charges in the early years of the nineteenth century enabled a new interpretation of chemical combination and the theory of valency. Significant improvements in... 

J. J. Thomson (1856-1940) performed extensive work in electrochemistry, atomic structure, and valency and his interest in chemistry led him to the construction of a series of models of the chemical atom.92... 

S. B. Sinclair, J. J. Thomson and the chemical atom from ether vortex to atomic decay , Ambix, 1987, 34, 89-116. 

Up to this point, we have a reasonable interpretation of definite evidence, beyond this, imagination must come into play. It is fair to assume that the process of evolution was extremely slow, and that each element was developed gradually and passed from an unfinished to a finished stage. The chemical atoms are now known to be extremely complex structures, each with an electropositive nucleus surrounded by electrons in rapid motion. That such a structure could have been developed instantaneously, with no previous preparation, is hardly probable, for the process was one of condensation, from lighter to heavier, and that, it would seem, must have acquired time. The process was one from relative simplicity of structure to relative complexity, and with the maximum condensation, as shown by uranium and thorium, a minimum of stability was reached. That is, so far as we now know for less Stable atoms may have been formed, to exist for a brief period and then vanish. Some of the radioactive elements which appear as products of the decay of uranium are of this kind. On that theme, more later. 

The following table gives the chemical atomic weights of several important elernents, found in this way. It is customary to take the chemical atomic weight of oxygen to be sixteen, so that for example, that of sulphur is 32, since an atom of sulphur is twice as heavy as one of oxygen, and the atomic... 

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