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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 cm^(3) of aluminium ? |
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Answer» Solution :(i) Cubic close - packing is the same as FACE - centred cubic. For fcc, `a=2sqrt2r = 2xx4.414xx125=354" PM"` (ii) Volum e of UNIT cell `=(354xx10^(-10)CM)^(3)=4.44xx10^(-23)cm^(3)` Number of unit cells in `1cm^(3)=(1)/(4.44xx10^(-23))=2.25xx10^(22)` |
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