The achievements and limitations

The electron, since its discovery, has assumed a role of increasing importance in chemistry. With the evolution of more satisfactory ideas of electronic structure, has come a widening knowledge of the chemical substances and reactions familiar to us. 

In this book we will consider the development of our knowledge of the electron from the efforts of Bohr to the situation as it is at the present day. We will then deal with some particular atoms and apply the newer concepts to compound formation. It is hoped that the results of this operation, though more complex than those of earlier theory, will bring greater satisfaction, and can better interpret the properties of the compounds considered. 

An atom is an essential building block of all matter. Its properties result from its components and dictate the properties of any compound in which it is included. The properties of a given atom will be modified by those of an atom with which it is associated, to give a new set of properties, which will be characteristic of the compound formed. 

An atom, considered simply, consists of a nucleus possessing an overall positive charge, surrounded by negatively charged electrons. The electrons are free to move independently of the nucleus—they are certainly attracted, to it—but can easily come under the influence of a second atom and its nucleus. 

We will consider the nucleus in no further depth than this. Its detailed structure is beyond the scope of this book, though the part played by the nucleus remains an appreciable one in its effect on the distribution of electrons in compounds and their resultant properties. 

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