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Question Answer

Question Answer

1.In an atom first shell has 2 electron  second shell has 8 electron third shell have 18 electron
. explain this arrangement on the basis of quantum number?

Answer

K shell          no. of orbital   total no. of electrons

n=1                                               
      l=0                 1s                               2
      m=0
      (s=-1/2, +1/2)

L shell
n=2                                                 
      l=0                  2s                               2
      m=0
      (s=-1/2, +1/2)

       l=1                2p                                   6
      m=-1 (s=-1/2, +1/2)
       m=0 (s=-1/2, +1/2)
       m=1 (s=-1/2, +1/2)
M shell
n=3                                                 
      l=0                   3s                                  2
      m=0
      (s=-1/2, +1/2)

       l=1                  3p                                  6
      m=-1 (s=-1/2, +1/2)
       m=0 (s=-1/2, +1/2)
       m=1 (s=-1/2, +1/2)
      
       l=2                    3d                                 10
      m=-2 (s=-1/2, +1/2)
       m=-1(s=-1/2, +1/2)
       m=0 (s=-1/2, +1/2)
       m=1 (s=-1/2, +1/2)
        m=2 (s=-1/2, +1/2)

  N shell

      n=4                                               
      l=0                    4s                                 2
      m=0
      (s=-1/2, +1/2)

       l=1                   4p                                  6
      m=-1 (s=-1/2, +1/2)
       m=0 (s=-1/2, +1/2)
       m=1 (s=-1/2, +1/2)
      
       l=2                     4d                                 10
      m=-2 (s=-1/2, +1/2)
       m=-1(s=-1/2, +1/2)
       m=0 (s=-1/2, +1/2)
       m=1 (s=-1/2, +1/2)
        m=2 (s=-1/2, +1/2)
     
        l=3                     4f                                14
       m=-3(s=-1/2, +1/2)
        m=-2(s=-1/2, +1/2)
        m=-1(s=-1/2, +1/2)
        m=0  (s=-1/2, +1/2)
       m=-1(s=-1/2, +1/2)
        m=2 (s=-1/2, +1/2)
        m=3 (s=-1/2, +1/2)

2.calculate effective nuclear charge (zeff) felt by 2p electron of oxygen?

ans.
 O             1s^2    2s^2  2p^4
(8)             (n-1)        n

S=  5×0.35 +2×0.85
S=  1.75+1.70
S= 3.45
Zeff=A-S
       = 8-3.45
       =  4.55

3.calculate effective nuclear charge (zeff) felt by 3p electron of chlorine?

ans.
 Cl          1s^2      2s^2  2p^6     3s^2  3p^5
(17)        (n-2)       ( n-1)                  n

S=  6×0.35 + 8× 0.85   +  2× 1.00
S =  2.10 + 6.80  + 2.00
S= 10.9
Z= 17-10.9= 6.1

4.calculate effective nuclear charge (zeff) felt by 4s electron of pottasium?
ans

 Cl          1s^2  2s^2  2p^6     3s^2  3p^5      4s^1
(17)                (n-2)                    (  n-1)              n

S=  0×0.35 + 8× 0.85  +  10× 1.00
S= 0+6.8+10.00
S=16.8
Zeff= 19-16.8
      =   2.2



     
       
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