2. Matter is classified into Pure substances- a type of matter that has fixed composition. Further classified into Elements and compounds Mixtures- a material made up of two or more substances that can be easily separated by physical means. Do not have fixed composition.

3. Pure substances Elements- A substance that has all the same kind of atoms in it is an element. The periodic table is the list of all the elements. Example- copper wire has all Cu atoms in it. The elements are represented by a symbol. Compounds- A substance in which the atoms of two or more elements are combined in fixed proportion. They can be represented by a formula. Example- H2O (water) is compound 2 H atoms combine with 1 O atom. CaCO3(chalk- calcium carbonate).

4. Mixtures Heterogeneous Mixtures- A mixture in which different materials can be distinguished easily. Example- pizza, salad, granite, concrete. Homogeneous Mixtures- A mixture contains two or more gaseous, liquid, or solid substances blended evenly throughout. Particles are so small that they cannot be seen with a microscope and will never settle to the bottom of the container. Example- soft drink, sugar dissolved in water

5. Colloids A type of mixture with particles that are larger than those in solution but not heavy to settle out. Example- milk, fog, paint, smoke, gelatin

6. Tyndall Effect It is a test to distinguish between solutions and colloids. A light of beam is invisible as it passes through a solution but can be seen easily as it passes through a colloid. This occurs because the particles in the colloid are larger enough to scatter light but those in solution are not.

7. Suspensions It is a heterogeneous mixture containing a liquid in which visible particles settle. example- muddy pond water- mud settles at the bottom