Introduction

Although the line between physics and chemistry is hazy, with this chapter we are definitely across it. Chemistry began with a search for a way to change ordinary metals into gold. This fruitless task, called alchemy by the Arabs, was not abandoned until the seventeenth century. At that time John Mayow and Robert Boyle in England, Jean Rey in France, and Georg Stahl in Germany, among others, started to look systematically into the properties of matter and how they change in chemical reactions.

After a look at what is meant by chemical change, we go on to consider the periodic law, a natural classification of the elements into groups with similar characteristics. As we shall find, the periodic law has its roots in atomic structure. This is not surprising, since the way in which electrons are arranged in an atom is what determines how that atom interacts with other atoms–in other words, how it behaves chemically.