1. Inorganic chemistry, which deals with the properties, behavior, and reactions of inorganic compounds. Inorganic compounds are those that do not contain carbon-hydrogen bonds. This includes all metals, as well as many nonmetals, such as sulfur, nitrogen, and oxygen.

2. Organic chemistry, which deals with the properties, behavior, and reactions of organic compounds. Organic compounds are those that contain carbon-hydrogen bonds. This includes all living organisms, as well as many synthetic materials, such as plastics, fuels, and pharmaceuticals.