* Elements: Elements are the simplest pure substances, like sodium (Na) and chlorine (Cl).

* Compounds: Compounds are formed when two or more elements chemically combine in a fixed ratio, like sodium chloride (NaCl), which is table salt.

* Mixtures: Mixtures are combinations of two or more substances that are not chemically bonded. They can be separated by physical means.

Salt water is a mixture of salt (NaCl) dissolved in water (H₂O). You can separate the salt from the water through evaporation, proving that they are not chemically bonded.