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Consider the ground state of Cr atom (Z = 24). The numbers of electrons with the azimuthal quantum numbers, = 1 and 2 are, respectively: (A) 16 and 5 (B) 12 and 5 (C) 16 and 4 (D) 12 and 4



Consider the ground state of Cr atom (Z = 24). The numbers of electrons with the azimuthal quantum numbers,  = 1 and 2 are, respectively:


        (A)    16 and 5


        (B)    12 and 5


        (C)    16 and 4


        (D)    12 and 4


 


Grade:upto college level

3 Answers

Aditi Chauhan
askIITians Faculty 396 Points
8 years ago

(B)

 

Sol.    = 1 p and  = 2 for d.

 

        Now Cr has configuration

 

        1s2 2s2 2p6 3s2 3p6 3d5 4s1

 

        Hence there are 12, p-electrons and 5, d-electrons

 

Aviral singh
15 Points
3 years ago
Answer is 2(second option)because the correct electronic configuration  of Cr is:1s2 1s2, 2s2, 2 2p6 p6, 3s2, 3p6, 4s1, 3d5.
Usually we consider the electronic configuration  as: 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d4.
But this is wrong because 3d4 wats to achieve half stability.So it takes 1 electron from 4s2.Now 4s2 becomes 4s1 and 3d4 becomes 3d5 and attains half stability.
Now, for l=1(azimuthal quantum number)subshell is p....
And here for subshell p, number of electrons(I.e.2p6 and 3p6)total no. Of electrons=12.
For l=2(azimuthal quantum number),subshell is d....and total number of electrons for subshell d(I.e.4d5)total no. Of electrons=5....
So the combination(12,5)....i.e.option(b) is correct.
 
 
 
Thank you🙏
 
Kushagra Madhukar
askIITians Faculty 629 Points
one year ago
Dear student,
Please find the solution to your problem.
 
Cr has electronic configuration
1s2 2s2 2p6 3s2 3p6 3d5 4s1
Hence there are 12, p-electrons and 5, d-electrons
 
Thanks and regards,
Kushagra

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