Introduction

The idea that  the matter consists of  minimum units, i.e. atoms,  was proposed by an ancient Greek philosopher, Demokritos (Ancient Greece, ~ B.C. 500).  "Atom" means "unable to be divided".

Demokritos thought that this world is made of the atoms which are moving in the "empty" which spread infinitely.

On the other hand, Aristoteles (Ancient Greece, B.C. 384 - 322) thought that the world is filled with continuous substances.

The view of the Aristoteles style was dominant in a period from the ancient to the medieval times.

If you take anything or an object around yourself and cut it into ever smaller and smaller pieces, you would find that it is made of a vast number of fine fundamental unit that we call atoms.

INTRODUCTION

It was proposed by Indian philosopher, maharishi Kanad, that if we go on dividing matter, we will get smaller and smaller particles of matter. Finally, we will get the smallest particle of matter, which cannot be divided further. John Dalton called these particles by the name atom, which means ‘indivisible’. It was further proposed that the particles of matter (atoms) normally exists in a combined form and various combination of particles give u s various kind of matter. This combined form of atoms is called molecules.

All matter is made up of small particles called atoms and molecules. Different kind of atoms and molecules have different properties due to which different kind of matter also show different properties