Question

Element having principle quantum number 3

Answer 1

Answer:

For n=4;l=0,1,2,3.

N=1 present K-shell and the number of elements having K shell =2

N=2 present L shell and the number of element having L shell =8

N=3 present M shell and the number of elements having M shell =18

N=4 present N shell and the number of elements having N shell =32

Total number =2+8+18+32=60