The document discusses free ion configurations, terms, and states. It introduces Russell-Saunders coupling where total angular momentum J is equal to the sum of orbital angular momentum L and spin angular momentum S. It provides the formula for calculating n, the number of possible electron configurations based on quantum numbers l and q, the number of electrons. It briefly describes Orgel diagrams which depict weak field complexes and provides an example. It also mentions correlation diagrams but provides no details.