The maximum number of electrons that can be accommodated in a shell is given by the formula 2n2, where n denotes the shell number. Thus, since for the K shell, n = 1, hence the maximum number of electrons that can be accommodated in the K shell is 2 X (1)2 = 2. Similarly, the L shell can accommodate a maximum of 8 electrons, while the M and the N shell can accommodate a maximum of 18 and 32 electrons respectively.
If, however, a given shell is the outermost shell, it cannot hold more than 8 electrons. For example, the M shell can hold a maximum of 18 electrons, but if it is the outermost shell, then it cannot hold more than 8 electrons. Similar is the case with the N shell. It has the capacity to hold maximum of 32 electrons. But if it is the outermost shell, then it cannot hold more than eight electrons.
