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Question
Q203) In an atom, which has 2K, 8L, 18M and 2N electrons in the ground state. The total number of electrons having magnetic quantum number, m = 0 is



SOLUTION

2K electron i.e. 2 electron in n =1
∴ values of l = 0 and m = 0
for m= 0, 2 electrons

8K electron .i.e n = 2 fully filled
∴ values of l = 0,1
for l =0 , m = 0
and l= 1 , m = +1 ,0 , -1
18M electron .i.e n = 3 fully filled
∴ values of l = 0,1, 2
for l =0 , m = 0
and l= 1 , m = +1 ,0 , -1
and l =2 m =+2, +1, 0, -1, -2
2N electron i.e n =4 only two electrons
∴ values of l = 0,1,2,3
have subhsell 4s, thus m =0

Now total m= 0 appear above =7
each m=0 have two electrons = 7×2 = 14 electrons
Answer:(d)