Sir mujhe please bataye ki no.. of valence electrons in an atom kyase count kareee for d block elements.....kyuki mujhe pata hey ki joh last shell mey electrons hey wohi valence electrons hota heyy par then Google pey no of valence electrons of Fe 8 dikha raha heyy Parr Mera answer 2 aa raha hey 4S pey 2 electrons hey isliyeee tohhh konsa sahi haiiiiii????? Please batayeee sir ji

Valence electrons count for d-block elements can indeed be confusing, especially because they involve both the (n-1)d and ns electrons.

Here's a detailed explanation to help you understand how to count the valence electrons in d-block elements:

Understanding Valence Electrons in d-block Elements

1. 
   

   General Configuration:

   • d-block elements (transition metals) generally have the electron configuration (n-1)d^1-10ns^0-2.
   • For example, iron (Fe) has an electron configuration of [Ar] 3d^6 4s^2.

2. 
   

   Valence Electrons:

   • Valence electrons are those electrons that are involved in chemical bonding.
   • 
     
   • For d-block elements, these include the ns electrons and the (n-1)d electrons.

Iron (Fe) as an Example

Let's look at iron (Fe):

• 
  
• Electron Configuration: [Ar] 3d^6 4s^2

Counting Valence Electrons

1. 
   

   4s Electrons:

   • Fe has 2 electrons in the 4s orbital.

2. 
   

   3d Electrons:

   • Fe has 6 electrons in the 3d orbital.

Total Valence Electrons

• 
  
• For Iron (Fe):
  • 4s electrons: 2
  • 3d electrons: 6

Therefore, the total number of valence electrons for Fe is 2 (4s) + 6 (3d) = 8 valence electrons.

Conclusion

When counting valence electrons for d-block elements:

• 
  
• Include both the ns and (n-1)d electrons.
• 
  
• For Fe, the 2 electrons in 4s and the 6 electrons in 3d sum up to 8 valence electrons.

Thus, the correct answer for the number of valence electrons in Fe is indeed 8, not 2.

Summary

• General Rule: For d-block elements, valence electrons = ns electrons + (n-1)d electrons.
• 
  
• Iron (Fe): Total valence electrons = 2 (from 4s) + 6 (from 3d) = 8.

Understanding this concept will help you accurately determine the valence electrons for other d-block elements as well.

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