Here it says determine the number of electrons that can be found in the 7th shell and D sub level. So step one tells me to determine the L value for either a given N value or from a sub shell or sublevel letter. Here they're telling me that it's D because it's D That means that we know that L is going to be two.

If they're just giving me an N value and some other quantum numbers, then I would have utilized this part of our map. Now we know L is equal to two if M sub L is not given. Use the L value to determine the number of orbitals. Remember M sub L is the range of L so M sub L would be -2 to two. So -2, -1, 0, +1, and +2.

That is a total of 5 orbitals and then based on the number of orbitals, find the number of electrons. Remember each orbital can hold a maximum of two electrons. If I multiply this by two, that means that I have 10 electrons that would be in the 7th shell and have a D sublevel letter.