One of the key ideas in classical chemistry is that every one chemical compounds may be represented as teams of atoms warranted along and chemical reactions may be represented because the creating and breaking of these bonds. Predicting the properties of chemical compounds from an outline of atoms and the way they bond is one in all the foremost goals of chemical science. to explain the atoms and bonds exactly, it's necessary to understand each wherever the nuclei of the atoms ar, and the way electrons ar distributed around them.