Introduction

It is always easy to distinguish the items from one another by sorting them on some basis. In malls or in shops we always get the things sorted at their respective places. In shops kids wear can be bought from kid section which cannot be found in any other section. Grocery shops also align the items in a systematic way.

There are all total 92 well known naturally occurring elements of which 70 are metals and remaining 20 are the non-metals. There are certain elements possessing the characteristics of both metals as well as non-metals. They are termed as metalloids. For instance, boron, silicon, germanium, arsenic, antimony, tellurium, and polonium.

But it could not exist for long because of the following limitations:

• Döbereiner’s triads could find only three triads; .i.e total of 9 elements only but actually there were many more elements known at that time.
• Therefore Dobereiner’s could not classify most of the elements known at that time.