7. Particles, Waves, and     Paradoxes   Previous PageNext Page

Chemistry was in bad shape at the beginning of this century. Most of the knowledge of chemical properties that we have covered in the first six chapters was available, but without the underlying models that would tie it together.

The usefulness of concepts of atoms, molecules, and moles was recognized, but there were still respectable chemists who doubted whether atoms had a real existence other than as conceptual models to account for observations. The periodic table organized chemical properties in a sensible manner, and had led to the successful prediction of properties of new elements, but no one knew why the table had the structure that it did. Ideas about the shapes of molecules were in their infancy.

Van't Hoff used the number of different substituted methane compounds that could be made to argue for tetrahedral bond geometry around carbon atoms, but there was no theory of chemical bonding to explain why this should be true.

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