The Atomic Theory

Thus we see that the properties of gases provide a substantial basis for developing the atomic theory. The gaseous state is, in many ways, the simplest state of matter for us to understand. The regularities we discover are susceptible to detailed mathematical interpretation. We shall examine these regularities in this chapter. We shall find that their interpretation, called the kinetic theory, provides an understanding of the meaning of temperature on the molecular level. 

Once again it is no surprise that the simple integer volume ratios are readily explained with the atomic theory. The atomic theory was devised for this purpose, as is indicated in Chapter 2. 

The initial set of experiments and the first few textbook chapters lay down a foundation for the course. The elements of scientific activity are immediately displayed, including the role of uncertainty. The atomic theory, the nature of matter in its various phases, and the mole concept are developed. Then an extended section of the course is devoted to the extraction of important chemical principles from relevant laboratory experience. The principles considered include energy, rate and equilibrium characteristics of chemical reactions, chemical periodicity, and chemical bonding in gases, liquids, and solids. The course concludes with several chapters of descriptive chemistry in which the applicability and worth of the chemical principles developed earlier are seen again and again. 

Atoms can form chemical bonds with one another to construct molecules. As we point out in Chapter 2, this is one of the fundamental features of the atomic theory. The details of chemical bonding appear in Chapters 9 and 10. 

Turning to contemporary atomic theory, the narrator argues that there are... 

Rocke suggests that, like the atomic theory, the benzene theory was both extremely popularbecause it was successfulawd disbelieved in realist terms. 52 In both cases, and in the case of the carbon tetrahedron, there were two compelling problems that deterred most chemists from believing they had a real, probably true theory. 

Volume 3 explains the systems of molecular and atomic weight, valences, the atomic theory, the system of classification of the elements, and the laws of chemical equilibrium. Here we find Lespieau s view that the goal of chemistry is the formule developee, not the formule brute, and that the atomic hypothesis gives us a striking interpretation and creates a language that is now adopted by all chemists, even those who reject the hypothesis of an indivisible primordial particle.30... 

According to the atomic theory the differences between what are termed "allotropic modifications" are generally ascribed to differences in the number and arrangement of the atoms constituting the molecules of such "modifications," and not to any differences in the atoms themselves. But we cannot argue that two such "allotropic modifications" or elements which are transmutable into one another... 

Although chemists wrestled with the problem, they found no logical solution. Further experimentation seemed only to make matters worse. When the French chemist Jean-Baptiste Dumas measured the densities of different kinds of vapors during the 1820s, he achieved results that were even more difficult to reconcile with the atomic theory. The theory couldn t be abandoned by this time it had become an integral part of chemistry. 

A Brief Summary of Atomic Theory, the Basis of the Periodic Table and Some Trends in Atomic Properties... 

Thomson, J. J. The Atomic Theory, The Romanes Lecture (1914), Oxford/ Clarendon Press Gloueestershire, U.K., 1914. 

In the classical era in Europe, the theory and practice of chemistry were pursued mainly by the ancient Greeks, who made many important discoveries in metallurgy in particular and who are also credited with proposing the earliest version of the atomic theory. The Greek chemical tradition declined when mysticism displaced the observational approach in the second century of the Common Era, and subsequently was largely lost in Europe after the fall of Rome in 410 c.E. In the 11th. century c.E., the quasiscience of alchemy returned to Europe via the Arabs, who also introduced Persian, Indian, and Chinese influences. 

Cannizzaro, Stanfslaa(l826-1910). An Italian chemist, known for his work in org chemistry and application of Avogadro s hypothesis to the atomic theory. The so-called "Cannizzaro... 

Students will demonstrate an understanding of the five basic atomic theories—the Dalton atom, the Thomson atom, the Rutherford atom, the Bohr atom, and the Schrodinger electron cloud model—and illustrate this understanding in a two-dimensional work of art. 

Patterson, Elizabeth C. John Dalton and the Atomic Theory The Biography of a Natural Philosopher (Doubleday, 1970). 

Tested hypotheses become theories or laws. The atomic theory—the most important of all chemical theories. 

As in the spin-polarized NR case, the convenience of having only two potentials to represent magnetic interactions is obtained at a price. This price includes some contamination of the SCF solutions with a mixture of multiplets, which can sometimes be resolved by projection techniques, including for example, the Slater Sum Rule of atomic theory. The ease of calculation of an R potential which treats exchange in open-shell heavy atom systems reasonably well, without introducing artificial (and incorrect) spin-polarization is a considerable advantage. 

Early Ideas About Matter Development of the Modern Atomic Theory The Discovery of Atomic Structure Atomic Numbers and Masses MiniLab 2.1 A Penny for Your Isotopes ChemLab Conservation of Matter... 

The first of these laws was established by Proust in 1799. Dalton himself proved the law of multiple proportions by his researches on olefiant gas and carburetted hydrogen, and on other substances. The third law first became apparent from the neglected work of Richter on the quantitative neutralisation of acids by bases (p. 146). Soon after the publication of the Atomic Theory, the great Swedish chemist, Berzelius, wrote to Dalton saying that the theory of multiple proportions is a mystery without the atomic hypothesis. ... 

According to Dalton s Atomic Theory, the simple atoms of a particular clement arc perfectly alike in weight and figure they can neither be created nor destroyed and they may unite in simple proportions with other simple atoms to fonn compound atoms [later called molecules], consisting of small whole numbers of the elements concerned. 

The Laws of Reciprocal and Multiple Proportions have ceased to have predictive scientific value. Their importance hes in the fact that they provided evidence that Dalton needed in 1807 to postulate his atomic theory. The reason for Richter s whole number ratios has since become obvious the simple ratios occur because atoms, although having different masses, react in simple ratios. Dalton s insistence that atoms cannot be split in chemical reactions holds true in modern chemistry. 

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