Question
Wed August 10, 2011 By:

The density of krypton(fcc) is 3.19g/cc. What is the radius of the atom?

Expert Reply
Wed August 10, 2011
Given density of krypton  = 3.19 g/cc
For fcc, Z = 4
 
we know that   

      d = (Z x M) / (a3 x NA)

Molar mass of  krypton = 83.8 g/mol

 Therefore, a3 = (4 x83.8) / (3.19 x 6.022 x 1023)
 
or,  a3 = 174.49 x 10-24
 
     a = 13.2 x 10-10 m
 
Now, for fcc    r =a/
 
r =  13.2 x 10-10 / (2 x 1.414)
  = 4.66 x 10-10
r =0.466 nm
Therefore the radius of the atom =0.466 nm
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