#### Answer

a) 3
b) 3
c) 3
d) n=3, l=2,
Possible values of $m_{l}$= -2, -1, 0, +1 or +2.

#### Work Step by Step

a) The number of subshells= the value of n= 3
b) For the p subshell, l=1.
Total number of orbitals= 2l+1= $2\times1+1=3$
c) Maximum value of l= n-1= 4-1= 3
d) n=3, l= azimuthal quantum number corresponding to the d subshell= 2.
Allowed values of $m_{l}$ ranges between the interval -l and +l. Therefore
$m_{l}$= -2, -1, 0, +1 or +2.