2.67 (a) How many subshells are associated with n = 4 ? (b) How many electrons will be present in the subshells having ms value of –1/2 for n = 4?


(a) n = 4 (Given)
For a given value of ‘n’, ‘l’ can have values from zero to (n – 1).
l = 0, 1, 2, 3
Thus, four sub-shells are associated with n = 4, which are s, p, d and f.

(b) Number of orbitals in the nth shell = n2
For n = 4
Number of orbitals = 16
If each orbital is taken fully, then it will have 1 electron with ms value of .
Number of electrons with ms value of -12 is 16.