Knowing that a no orbital can accommodate more than two electrons,we can predict the maximum number of electrons in each layer or sub-layer ,It is possible when :
* Only two electrons can be assigned to an s orbital.
* three orbitals in a sub-layer p can accommodate two electrons, this sublayer can accommodate a maximum of six electrons.
* The five d orbitals of a sub-layer can accommodate a total of ten electrons.
hope this helps!