Point out the followings:
(a) How many energy subshells are pssible in ` n=3` level ?
(b) How many orbitals of all kinds are possible in ` n=3` level ?

Explanation

(a) Subshells in n = 3 energy level
We know that the subshells are given by different values of l.
For n = 3, the possible values of l and 0, 1, and 2.
`l = 0` , s - subshell, l = 1, p- subshell, l = 2, d - subshell.
(b) Number of orbitals.
For n = 3, there are one s, three p and five d-orbitals.
This makes total of nine orbitals in n = 3 level.