1. Grouping together of matter with similar properties is called classification. Classification makes the study of matter easy, systematic and more scientific.
2. Elements and compounds are pure substances. Mixtures are impure substances.
3. Elements are made up of similar kinds of atoms. They are classified as metals, non-metals and metalloids.
4. Metals are usually solids. They shine and allow heat and electricity to pass through them.
5. Non-metals are usually gases or liquids. They do not shine and do not allow heat and electricity to pass through them.
6. Metalloids show properties of metals as well as non-metals.
7. Elements combine chemically in a fixed ratio to form compounds.
8. The constituents of a mixture do not combine chemically with each other. They are present in varying ratios. Hence, mixtures do not have fixed properties.