Development of Atomic Theory

Periodic properties of the elements as an apparent function of their atomic weights 

Cathode rays and their negative nature (electron) 

Canal rays and their positive nature (proton) 

Electron (Crookes cathode rays ) charge/mass ratio 

Bohr model of atomic structure Atomic number 

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The subsequent development of atomic theory and quantum mechanics has provided an explana-... 

Proc.RSL A113 (1927) 621641 Pascual Jordan, "Ueber eine neue Begriindung der Quantenmechanik," ZP 40 (1927) 809838 Werner Heisenberg, "Ueber den anschaulichen Inhalt der quantentheoretischen Kinematik und Mechanik," ZP 43 (1927) 172198. Bohr first discussed the principle of complementarity at a conference in Como in 1927 see Niels Bohr, "The Quantum Postulate and the Recent Development of Atomic Theory," Nature 121 (1928) 580590. 

The Quantum Postulate and the Recent Development of Atomic Theory." Nature 121 (1928) 580590. 

Having recognized the close quantitative connection between optical properties and collision dynamics at this stage of development of atomic theory is a remarkable example of Bohr s physical intuition. 

The following discussion of catalytic activity can be viewed only as a preliminary attempt to describe the important features of the field in terms of the language which has arisen out of the development of atomic theory, and which it is felt must eventually become the lingua franca of all of chemistry if the tradition which desires to describe chemical phenomena in terms of atomic behavior is continued. This language has arisen out of the pioneer work of Wigner, Pelzer, Eyring, Polanyi (1), and their many associates and coworkers during the very fruitful period of activity in the vicinity of 1930 when the evolution of atomic mechanics first made it possible to discuss chemical phenomena, particularly rate processes, from a unified and selfconsistent viewpoint. 

Russell, Berzelius and the Development of Atomic Theory, Cardwell, Dalton the Progress of Science, 259-273. 

Despite the critical attacks by Dalton, the contributions of Gay-Lussac and Avogadro turned out to be most important to the development of atomic theory. Their efforts, however, were not widely recognized until after their deaths. Gay-Lussac died 10 years prior to the I860 conference, and Avogadro died 4 years prior. 

Precision measurement of energy intervals in hydrogen and helium has been fundamental to the development of atomic theory. Relativistic and quantum-electrodynamic contributions scale with various powers of Z. Hence more information is gained by extending precise measurements to one- and two-electron ions. Laser spectroscopy is restricted to certain special transitions which fall in the infrared, visible or near-ultraviolet, and from which a useful signal can be obtained. However, where applicable, it provides precision tests of theory. The focus of this review is laser spectroscopy of the n = 2 levels of moderate-Z helium-like and hydrogen-like ions. Previous reviews may be found in [1,2,3],... 

It s impossible to weigh or isolate a single atom. We know that the atom is so tiny that we cannot feel it by using our senses. Therefore, the development of atomic theories have been based on indirect methods. At the beginning of the 19 century, the existence of atoms had been a point of contention. Erstwhile, Muslim scientist Jabir Bin Hayyan (721-815) had discovered that an individual atom could be split to release a huge amount of energy. 

Chemistry, has a very interesting history and the works of Priestley, Lavoisier, Davy, Black and Dalton etc. can be given this type of treatment. The gradual development of atomic theory can be unfolded gradually by this method which will be quite interesting. 

Trace the history of the development of atomic theory, beginning with Dalton. 

Explain the critical role of spectroscopy in the development of atomic theory and in our everyday lives. 

The theory of atomic structure has progressed rapidly, from a very primitive level to its present point of sophistication, in a relatively short time. We briefly summarize our present knowledge of the composition of the atom in Section 2.2. Then in Section 2.3 we present an outline of the significant scientific discoveries that spurred development of atomic theory. Before we proceed, let us insert a note of caution. We must not think of the present picture of the atom as final. Scientific inquiry continues, and we should view the present theory as a step in an evolutionary process. Theories are subject to constant refinement, as was noted in our discussion of the scientific method. 

In the 17th and 18th centuries, the gradual development of atomic theories caused affinity to come to mean a tendency of substances to combine with each other as a result of the forces between them resulting from the distinctive characteristics of the particles involved. A chemical reaction was seen as a process in which elementary particles interacted with one another as a result of their chemical affinities. In this Affinity Corpuscular Model, the rate of a reaction was related to the different degrees of affinity between the particles and depended on their readiness to occur. 

The development of atomic spectroscopic techniques and their appHcation to fundamental studies fostered the concurrent development of atomic theory and quantum mechanics. In turn, the better understanding of atomic theory has led to the implementation of many beneficial techniques and instrumental features in atomic spectroscopy, particularly for the reduction or elimination of interferences and background. 

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