A general way to calculate the number of states that arise from a given configuration is as follows. Calculate the combinations of m_l and m_s for the first electron, and call that number n. The number of combinations used is the number of electrons, which we call m. The number of unused combinations is n − m. According to probability theory, the number of distinct permutations that arise from distributing the m electrons among the n combinations is n! / [m!(n – m)!]. For example, the number of states arising from a p² configuration is 6! / [2!4!] = 15, which is the result obtained in Section 22.2. Using this formula, calculate the number of possible ways to place five electrons in a d subshell. What is the ground-state term for the d⁵ configuration and how many states does the term include?