The question is incomplete; the complete question is;
There are 118 known elements. How many elements have atoms, in their ground state, with core electrons whose quantum numbers are n=3 and l=1?
a. 10
b. 6
c. 100
d. 18
Answer:
c. 100
Explanation:
If we look closely at the periodic table, we will notice that there 100 elements that occur after argon whose electronic configuration is; 1s2 2s2 2p6 3s2 3p6.
This means that there every other element after argon must have a 3p sublevel as part of its core electrons. In the 3p sublevel, n=3 and l=1.
If we diligently count the number of elements from potassium (immediately after argon) to Oganesson (element 118) we have a total of 100 elements all having core electrons of quantum numbers are n=3 and l=1.
