PLz solve it with reason.....??

Question

If elements with principal quantum no n>4 were not allowed in nature,the no of possible elements would be:-
1)60
2)32
3)4
4)64

Answer 1

My answer would be 36. All elements 36 and under have n=4 or less. The principle quantum number is the number of the series (or period) of that element. For instance, Fluorine has an electron configuration of 1s2, 2s2, 2p5. Since the highest level is "2" it will be found in the second period of the periodic table.