Question

1. a) What are the subshells possible in n=3 energy level?
b) How many unpaired electrons are present in the ground state of P (Z=15)
c) How many electrons in zinc (Z=30) have (n+l ) value = 4?

Answer 1

a) for n=3 , there are l=0,1,2 possible values. Since, l can never be equal or greater than n it has all possible values less than that of n. So s,p,d subshells are possible with n=3.
b) electronic comfiguration of P in ground state is 1s2 2s2 2p6 3s2 3p3. In p subshell there are 3 electrons which occupy the position in all three orbitals in accordance with Hund's rule. So there are 3 unpaired electrons in ground state of P.
c) electronic configuration of Zn is 1s2 2s2 2p6 3s2 3p6 4s2 3d10
For 3p = n+l = 3+1 = 4 ,
4s = 4+0 = 4
Hence 3p and 4s has n+l =4 value.
Thanks :)