Question: how many electrons are possible in all shells with n+l=5?
Answer: For the 5s orbital, n = 5 and l =0, therefore (n + l) = 5. An s subshell has only one orbital and as an orbital can hold a maximum of two electrons, therefore the maximum number of electrons that would be present in the 5s orbital would be 2. For the 4p orbital, n = 4 and l = 1, therefore (n + l) = 5.