In my textbook it says that the maximum number of electrons that can fit in any given shell is given by 2n². Which would mean 2 electrons could fit in the first shell, 8 could fit in the second shell, 18 in the third shell, and 32 in the fourth shell. However, I was previously taught that the maximum number of electrons in the first orbit is 2, 8 in the second orbit, 8 in the third shell, 18 in the fourth orbit, 18 in the fifth orbit, 32 in the sixth orbit. I am fairly sure that orbits and shells are the same thing.