1. The problem statement, all variables and given/known data n = 3 Using the fact that there are two quantum states for each value of l and m because of electron spin. Find the total number of electron states with n = 3. 2. Relevant equations 3. The attempt at a solution I've already determined that l = 0, 1, 2 and m = -2, -1, 0, 1, 2 So, given the information I figured it would be 8 * 2 = 16 quantum states. Unfortunately, it's supposed to be 18 quantum states and I fail to see where they pick up 2 extra ones. Does anyone know what I am doing incorrectly?