Atoms are extremely small particles that constitute a specific type of chemical element and that gives elements their property like color, density, melting point, boiling point, and thermal and electrical conductivity. Elements are substances made from one type of atom that cannot be separated into simpler substances, like sodium, hydrogen, oxygen, and chloride. Lastly, Compounds are substances consisting of two or more elements, whose atoms are chemically joined together; water and salt are examples of compounds because the first is made of hydrogen and oxygen, while the latter is made up of sodium and chloride.