Aluminium crystallises in a face centred cubic structure, it's atomic radius is $125 \mathrm{pm} .$ What is…

Aluminium crystallises in a face centred cubic structure, it's atomic radius is $125 \mathrm{pm} .$ What is the edge length of unit cell?
  1. $280 \mathrm{pm}$
  2. $353.5 \mathrm{pm}$
  3. $335.5 \mathrm{pm}$
  4. $288.6 \mathrm{pm}$

Solution

For fcc unit cell, $r=\frac{a}{2 \sqrt{2}}$ $\therefore a=r(2 \sqrt{2})=125(2 \sqrt{2})=353.5 \mathrm{pm}$

Asked in: MHT CET 2020 (14 Oct Shift 2)

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