Max # of electrons in an atom whose highest-energy electrons have n=5

[paridiso]

What is the maximum number of electrons in an atom whose highest-energy electrons have the principal quantum number ?

I tried 54 and 110. Neither was correct.

 

[Bohrok]

Probably yes, but is the atom in its ground state?

What are the subshells in the n=5 shell? Which element has the highest atomic number in those subshells?

 

[paridiso]

The first sentence I posted is everything given in the problem. I'm assuming it's in a ground state but I'm not sure.