I don't think 6 is right. See my answer above.
https://www.jiskha.com/questions/1836733/an-atom-in-its-ground-state-contains-18-electrons-how-many-of-these-electrons-are-in
an atom in its ground state contains 18 electrons . how many of these electrons are in orbital with l=0 values
2 answers
oops. 6 is right. I'm wrong.