1.25     Aluminium crystallises in a cubic close-packed structure. Its metallic radius is 125 pm.
                    (ii) How many unit cells are there in 1.00 cm3 of aluminium?

Answers (1)

For cubic close-packed structure,

we have a=2\sqrt{2} . r

Given : r=125 pm

           a =2\times 1.414\times 125

           a=354 pm

the volume of one unit cell =a^{3}=354^{3}

                               =(354\times 10^{-10})^{3}                    

                             =4.4 \times 10^{-23} cm^{3}

Total unit cells in 1.00 cm3=\frac{total \, \, volume }{size \, \, of\, \, unit\, \, cell}

                                            =\frac{1 cm^3}{4.4\times 10^{-23} cm^3}

                                            =2.27 \times 1022 unit\, \, cell

 

 

 

 

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