Although a good background in chemistry is not essential to get through this course, it is necessary that one understands some very basic concepts in chemistry. Once you read this review and understand the concepts within it, you will have a strong base from which to build upon an understanding of the workings of the nervous system.
All matter is made up of molecules.
A molecule consists of two or more atoms linked together by chemical bonds . An atom has a central nucleus surrounded by a cloud of electrons. They are about equal in mass. The number of protons in the nucleus is called its Atomic Number . The total number of protons and neutrons is its Atomic Weight .