The sum of electrons present in all sub shells of an atom with m_s value of + 1 2 for n=4 and m_s value of - 1 2 for n =3 is

Step-by-step solution

No. of electrons in ' n ' shell =2 n^2 n =4 ; 2 n ^2=32 e and n =3 ; 2 n ^2=18 e Half of the electrons in one shell has (+ 1 2 ) spin and half of them has (- 1 2 ) spin. Total no. of electrons = 32 2 + 18 2 =25 e