This program covers the very important topic of atomic mass of an element. We begin by discussing the structure of the atom and how this can be used to arrive at a number that represents the relative mass of the atom. This quantity will be used in virtually every calculation in chemistry. The entire lesson is taught by working example problems beginning with the easier ones and gradually progressing to the harder problems. Emphasis is placed on giving students confidence in their skills by gradual repetition so that the skills learned in this section are committed to long term memory.