NCERT Question 18 - Chapter 4 Class 9 - Structure of Atom

Last updated at July 14, 2026 by

 Which one of the following is a correct electronic configuration of sodium?

(a) 2,8   (b) 8,2,1 (c) 2,1,8 (d) 2,8,1

 

Answer

 

(d) 2,8,1

 

Explanation-

 

  • Atomic number of Sodium = 11
  • Therefore, it has 11 electrons
  • Electronic configuration of Sodium is as follows:

K Shell = 2 e -

L Shell = 8 e -

M Shell = 1 e -

  • Hence, its electronic configuration is 2,8,1

 

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