NEET Chemistry The Solid State Questions Solved


Atomic radius of silver is 144.5 pm. The unit cell of silver is a face centred cube. Calculate the density of silver.

(1) 10.50 g/cm3

(2) 16.50 g/cm3

(3) 12.30 g/cm3

(4) 15.50 g/cm3

(1) For (fcc) unit cell, atoms touch each other along the face diagonal.

Hence, Atomic radius (R) =a24

a=4R2=42×144.5pm=408.70pm=408.70×1010cm

Density (D) =ZMVN0, V = a3

D = ZMa3N0; where Z for (fcc) unit cell = 4 , Avagadro’s number (N0)=6.023×1023, Volume of cube (V) =(408.70×1010)3cm3 and M (Mol. wt.) of silver = 108,

D =4×108(408.70×1010)3×6.023×1023=10.50g/cm3  

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