Question 1 Page 50 - Chapter 4 Class 9 - Structure of Atom

Write the distribution of electrons in carbon and sodium atoms.

Answer

Based on the Bohr-Bury scheme, we know that the maximum number of electrons that can be present in a particular energy shell of an atom is given by 2n 2 , where “n” is the number of energy shells.

(i) Carbon

Atomic number of Carbon = 6

Therefore, number of electrons in Carbon = 6

• 2 of them are held in K Shell (as K Shell can hold max 2 electrons)
• 4 of them are held in L Shell (as L Shell can hold max 8 electrons)

  
  So, 

  K Shell - 2

  L Shell - 4

(ii) Sodium

Atomic number of Sodium = 11

Therefore, number of electrons in Sodium = 11

• 2 of them are held in K Shell (as K Shell can hold max 2 electrons)
• 8 of them are held in L Shell (as L Shell can hold max 8 electrons)

Remaining 1 is held in M Shell

So, 

K Shell - 2

L Shell - 8

M Shell - 1