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The electrons identified by quantum numbers n and l :

(1) n = 4, l = 1      (2)  n = 4, l = 0     (3) n = 3, l = 2     (4) n = 3 , l = 1

Can be placed in order of increasing energy as :

  • Option 1)

    (4)< (2)< (3)< (1)

  • Option 2)

    (2)< (4)< (1)< (3)

  • Option 3)

    (1)< (3)< (2)< (4)

  • Option 4)

    (3)< (4)< (2)< (1)

 

Answers (3)

best_answer

As discussed in the concept

Principal Quantum Number (n) -

 It is a positive integer with value of n = 1,2,3.......

-

 

 and

Azimuthal Quantum Number(l) -

For a given value of n, l can have n values ranging from 0 to n – 1, that is, for a given value of n, the possible value of l are : l = 0, 1, 2, ....( n –1)

-

 

 (1)\; n=4,l=1\Rightarrow 4p

(2)\; n=4,l=0\Rightarrow 4s

(3)\; n=3,l=2\Rightarrow 3d

(4)\; n=3,l=1\Rightarrow 3p

Increasing order of energy is

3p< 4s< 3d< 4p

(4)< (2)< (3)< (1)  

Alternatively,

For\; \; \; \; (1)\; n+l=5;n=4

              \; \; \; \; \; \; (2)\; n+l=4;n=4

              \; \; \; \; \; \; (3)\; n+l=5;n=3

              \; \; \; \; \; \; (4)\; n+l=4;n=3

Lower\; n+l\; means\; less\; energy \; and \; if\; for\; two\; subshells\; n+l\;

is\; same\; than\; lower\; n,lower \; will \; be\; the\; energy.

Thus correct order is (4) < (2) < (3) < (1)


Option 1)

(4)< (2)< (3)< (1)

Correct option

Option 2)

(2)< (4)< (1)< (3)

Incorrect option

Option 3)

(1)< (3)< (2)< (4)

Incorrect option

Option 4)

(3)< (4)< (2)< (1)

Incorrect option

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