10th Class Science Periodic Classification of Elements Lavoisiers Classification

       Introduction

So far Scientists have discovered 118 elements. Some of these elements are in free states, while the others in combined state. But all these elements were not discovered in a day. It has taken a long time to do so. When a very few elements were known, study of these elements were easier. But with the increase in the number of elements, it became difficult to study the properties of all of them separately. So an attempt has been made from time to time to classify these elements into groups, depending upon their physical and chemical properties. The study of the properties of element of a particular group helps the scientists to predict the properties of other elements of that group. In this chapter we will discuss about the classification of the elements into various groups on the basis of their properties.

           Lavoisier's Classification

Lavoisier's classification was based on the basis of the physical properties of the elements, such as hardness, malleability and lustre. He classified the elements into two groups, i.e. as metals and non metals. The first elements, he classified, was sodium and lead. He classified them as metal on the basis of their physical properties. But his basis of classification has many limitations. The properties such as hardness, malleability and lustre are the common physical properties of only some elements and other elements were entirely different. There was no place for the elements with properties resembling hose of metals, as well as of non metals. Therefore, this method of classification was found to be inadequate for classification of all the elements.