Intensive properties are fundamental properties of the material. These include density, transition temperatures, color, and all chemical properties. Intensive properties are the same for all samples of the material. Physical changes are changes which do not involve a change in the composition of the material. Examples are phase changes and dissolution.
Chemical changes involve conversion of a set of materials into other materials.
There are only about 100 naturally occuring elements known on earth, and a few more can be made through nuclear reactions. Elements cannot be broken down into any simpler chemical substance. Examples of elements are gold, silver, oxygen, nitrogen, hydrogen, carbon, copper, iron, etc. When two or more elements combine chemically, compounds are formed. All samples of compounds have exactly the same percentages of the elements making up the compound.