a. Multimolercular cooloids: A large number of atoms or smaller molecules of a substance on dissolution aggregate together to form species having size (diameter lt1mm) in the colloidal range `(1-1000nm)` . Such species are, known as multimolecular colloids. For example, a sulphur sol consist of particles containing a thousand or more `S_(S)` sulphur molecules.
b. Macromolecular colloids: Macromolecules (starch, cellulose, proteins and nylon, polyethene, etc.) when dissolved in suitable solvent form a solution wherein the size of the macromolecules may fall within the colloidal range. Such systems are called macromolecular colloids.