Chemistry is the part of science that is related to the composition, properties of structure and matter, and the changes that occur under the influence of chemical reactions. It is the study of atoms, molecules, crystals, and their different bonding to form different structures having various chemical properties. It also deals with certain parameters like energy, entropy and spontaneity of chemical reactions.

Chemistry can be subdivided into three categories: Physical, Organic and Inorganic. The physical chemistry deals with the components of a structure, the energy aspects of a reaction, and other various analytical and mathematical aspects of chemistry. The inorganic chemistry mainly deals with the study of inorganic matter, generally metals, and their structure and different physical and chemical properties. Organic chemistry is the study of the organic matter found in the nature, and how reactions have influence over different organic substances. However, one can classify further based on specialization such as biochemistry and neurochemistry.