There are three states of matter – solid, liquid, and gas. Each matter has its own distinct physical properties. Changes in the temperature of a particular type of matter can cause matter to change from one state to another. This type of change is called a physical change because only the physical properties of matter have been changed; its composition remains the same. Matter can also be changed chemically. A chemical change converts matter into a new substance. Chemical properties describe how a substance can react to form another substance.
All matters are made up of atoms which consist of a nucleus containing positively charged protons and neutrons that have no electrical charge. Negatively charged electrons travel around the nucleus. The chemical and physical properties of matter can be explained in terms of electrons, protons, and neutrons. Substances containing only one type of atom are called elements. A compound is formed when two or more elements are combined in a chemical reaction. Each compound has its own unique chemical and physical properties. A molecule is made up of two or more atoms. Molecules can be formed by atoms from different elements as well as some atoms from a single element.
Mixtures are composed of two or more substances; and each retains its physical properties. A chemical reaction does not occur when a mixture forms. Mixtures can be separated by physical means, such as evaporation, filtering or magnetism, into their components parts.