The Atomic Theory states that All matter is made up of tiny particles called atoms Atoms of one element are the same. When other atoms combine with other atoms they create molecules. No ordinary means can destroy atoms or create atoms. Molecules contain identical atoms, Compounds contain atoms of at least two different elements. Element Tables Links to a Visual Chemistry site.
Physical changes are changes in which there is no new matter produced.
A chemical change or reaction is in which one or more new substances are formed. There are certain clues to help you identify what change a substance has undergone. They are shown below. Chemical changes are referred to as a chemical reaction. Any substance used up in the reaction is called a reactant.