Subatomic structure

From 50 years to 100 years after Dalton proposed his theory, various discoveries showed that the atom is not indivisible, but really is composed of parts. Natural radioactivity and the interaction of electricity with matter are two different types of evidence for this subatomic structure. The most important subatomic particles are listed in Table 3-2, along with their most important properties. The protons and neutrons occur in a very tiny nucleus (plural, nuclei). The electrons occur outside the nucleus. 

TREE DIAGRAM ILLUSTRATING THE HIERARCHY OF ELEMENTS, ISOTOPES, AND SUBATOMIC STRUCTURES. 

The subatomic structure of the atom began to emerge in the late nineteenth and early twentieth centuries, thanks to the development of the Crookes [after Sir William Crookes (1832-1919)] tube and the work of J.J. Thomson. Iso-... 

Hints of Subatomic Structure Mass and Charge of the Electron... 

AOx, CP, and tree and fungal laccases (Figure 8.5) [69]. Comparisons among the ground-state distribution of the Cu—S(cys) stretching vibration in the T1 copper site in each of these proteins show that they differ in strength. The Cu—S(cys) bond is one of the three essential coordination complexes of copper that defines the T1 site in MCOs and other copper proteins and is the major factor in electron transfer from the substrate to the trinuclear center [40,85]. Hence, RR spectroscopy can provide valuable information on how subatomic structural variations at this coordination can drive the functional properties of electron transfer at the T1 site. 

Thus, in the 70-year period from 1911 to 1981, NMR went through the stages of being an unsuspected property of unknown subatomic structures, through a period of importance only to basic physics, followed by aperiod during which it was developed as a tool for specialized chemical applications, and finally becoming a crucial medical tool useful to millions of patients and employing thousands of workers. 

There are two senses to this abstraction. First, the element is abstract because it is the result of an active effort to detach significant relevant features from the particular local context in which the elements exhibit their chemical action. No two reactions are identical in every detail, but the salient features of a series of similar reactions can be abstracted by the senses of experienced chemists with or without the aid of their instruments. But there is a second and less concrete form of abstraction involved in the construction of the explanatory structure of the periodic system. The idea that macroscopic chemical properties depend on an invisible causal factor (subatomic structure whether it is indicated by atomic number or atomic weight) that can be inferred based on a theoretical construction represents another significant form of abstraction. In this respect, the chemical element is close to a mathematical abstraction. Thus, it becomes an instrument that allows one to construct a series that is assumed to lie behind and to be more fundamental than all individual, local, observable chemical changes. This abstraction allows the chemist to describe the order behind the apparently chaotic multiplicity of the phenomenal world. 

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