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NEET2016Chemistryd and f Block ElementsActual

The electronic configurations of Eu (Atomic no. 63 ), Gd (Atomic no. 64 ) and Tb (Atomic no. 65 ) are:

Options

  1. AX e 4 f 7 6 s 2 , X e 4 f 8 6 s 2 a n d X e 4 f 8 5 d 1 6 s 2
  2. BX e 4 f 6 5 d 1 6 s 2 , X e 4 f 7 5 d 1 6 s 2 a n d X e 4 f 9 6 s 2
  3. CX e 4 f 6 5 d 1 6 s 2 , X e 4 f 7 5 d 1 6 s 2 a n d X e 4 f 8 5 d 1 6 s 2
  4. DX e 4 f 7 6 s 2 , X e 4 f 7 5 d 1 6 s 2 a n d X e 4 f 9 6 s 2

Correct answer

D. X e 4 f 7 6 s 2 , X e 4 f 7 5 d 1 6 s 2 a n d X e 4 f 9 6 s 2

Step-by-step solution

The electronic configurations of Eu (Atomic no. 63), Gd (Atomic no. 64) and Tb (Atomic no. 65) are: E u - X e 4 f 7 , 6 s 2 G d - X e 4 f 7 , 5 d 1 , 6 s 2 Tb - X e 4 f 9 , 6 s 2

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