Question

The density of copper is 8.95 g `cm^(-3)` .It has a face centred cubic structure .What is the radius of copper atom?
Atomic mass Cu =63.5 `gmol^(-1)N_(A)=6.02xx10^(23) mol^(-1)`

Answer 1

`d=(Zm)/(a^(3)xxNa)`
`rarr 8.95=(4xx63.5)/(a^(3)xx6.02xx10^(23)`
`a^(3)=(4xx63.5)/(8.95xx6.02xx10^(23)=4.71xx10^(-23)=.0047xx10^(-2)a=0.167xx10^(-7)`
`r=(a)/(2sqrt(2))=(0.167xx10^(-7))/(2xx1.414)`=127.8 PM