Aluminium crystallises in a cubic close- | Class 12 Chemistry Chapter The Solid State, The Solid State NCERT Solutions

Question:

Aluminium crystallises in a cubic close-packed structure. Its metallic radius is 125 pm.

(i) What is the length of the side of the unit cell?

(ii) How many unit cells are there in 1.00 cm3of aluminium?

Answer:

In a cubic close packed structure,the length of the side of unit cell is related to radius by an equation r = a/2√2

Or

a = r x 2√2

Putting the values in the equation, we get

a = 125 x 2 x 1.414 = 353.5 pm

Volume of the unit cell= (353.5 x 10-10)3 = 4.42 x 10-23

Number of unit cells in 1 cm3 = 1 / 4.42 x 10-23 = 2.26 x 1022 unit cells.

 


Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

  • Read the question carefully and focus on the core concept being asked.
  • Reference examples and data from the chapter when answering questions about The Solid State.
  • Review previous year question papers to get an idea of how such questions may be framed in exams.
  • Practice answering questions within the time limit to improve your speed and accuracy.
  • Discuss your answers with your teachers or peers to get feedback and improve your understanding.

Comments

Comment(s) on this Question

Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 2 , Question 24: Aluminium crystallises in a cubic close-packed structure. Its metallic radius is 125 pm. (i) What....