Question

aluminium crystallises in a cubic close packed structure. it's metallic radius is 125 pm.what is the length of the side of the unit cell and how many unit cells are there in 1.00 cm^3 of aluminium?

Answer 1

In ccp=fcc

a=22–√r=2×1.414×125a=22r=2×1.414×125pm=354pm

Volume of one unit cell =a3=(354×10−8cm)3a3=(354×10−8cm)3

Unit cell in 1cm3=1(3.54×10−8)3cm3=1(3.54×10−8)3

⇒2.26×1022

Answer 2

Answer:

2.26×10^22

Explanation:

a=2√2r

a=125×2×1.414

= 353.5pm

volume of unit cell =(353.5×10^-10)^3

=4.42×10^-23

no. of unit cell in 1cm^3 =

1/ 4.42×10^-23

= 2.26×10^22unit cell