Question

An element crystallizes in bcc and its atom has a radius of 173.2pm. If the
atomic mass of the element is 100 g, find the density.

Answer 1

Explanation:

An element (atomic mass = 100 g/mol) having bcc structure has unit cell edge length 400 pm. The density (in g cm ^-3 ) of the element is:

5.188

Given, M = 100 g/mol, a = 400pm

For BCC -

n=8×

8

1

+1=2

As we know,

Density=

a

3

×N

A

n×M

=

(400×10

−10

)

3

×6.02×10

23

2×100

=5.188 g cm

−3

(∵400pm=400×10

−10

cm)