Question

li has a bcc structure. it's density is 530 kg m^-3 and it's atomic mass is 6.94 g mol -1. calculate the edge length of a unit cell of lithium metal​

Answer 1

Answer:

Explanation:

Density, d=530kg/m  

3

=0.530g/cm  

3

 

(∵1kg/m  

3

=10  

−3

g/cm  

3

)

Molar atomic mass, M=6.94g/mol

For bcc unit cell, the number of atoms per unit cell, Z=2

Density, d=  

a  

3

N  

A

​

 

ZM

​

 

0.530=  

a  

3

×6.023×10  

23

 

2×6.94

​

 

a  

3

=4.34×10  

−23

 

⇒a=3.52×10  

−8

cm

The edge length, a=3.52×10  

−8

cm=352×10  

−12

m=352pm

(∵1m=100cm and 1pm=10  

−12

m)