If electron with principal quantum number `n gt 4` were not allowed in nature , the number of possible element would be

Options

A. 60
B. 32
C. 4
D. 64

Answer

A

Explanation

No. of electron that can accommodate in `n^(th)` shell `= 2n^(2)`
Total numbe of elements `= 2(1)^(n) + 2(2)^(2) + 2(3)^(2) + 2(4)^(2) = 60`