6.1 THE NEED FOR CLASSIFICATION OF ELEMENTS
Before the beginning of eighteenth century, only a very few elements were known and it was quite easy to study and remember their individual properties. In 1800, only 31 elements were known. This number of elements grew to 63 by 1865. With the discovery of large number of elements it became difficult to study individually the properties of these elements and their compounds. At this stage, the scientists felt the need of some simple methods to facilitate the study of the properties of various elements and their compounds. After numerous attempts the scientists were ultimately successful in arranging the elements in such a way so that similar elements were grouped together and different elements were separated.
The arrangement of elements in such a way that the similar elements fall within same vertical group and the dissimilar elements ate separated, is known as classification of elements.