Matter may be classified into pure elements, chemical compounds that contain many different elements.
Physically, the substances can be classified as mixtures and pure substances. Pure substances are homogeneous.
Mixtures can be a homogeneous mixture, colloid and heterogeneous mixture.
Any substance or matter can exist in each of three (or four) states :
Solid, liquid, gas (and plasma) depending on pressure, and temperature.
These are states of matter and not classification.