Question

coordination number of eight. The crystal class is
(1) Face-centred cube (2) Simple cube
JEET & AIIMS
Lithium has a bcc structure. Its density is
530 kg m and its atomic mass is 6.94 g mol-
Calculate the edge length of a unit cell of Lithium
metal (NA = 6.02 x 1023 mot') [NEET-2016]
(1) 264 pm
(2) 154 pm
(3) 352 pm
(4) 527 pm​

Answer 1

Answer:

FOR THE FIRST QUESTION YOUR ANSWERIS

The intermetallic compound Li−Ag crystallizes in a cubic lattice in which both lithium and silver have a coordination number of eight. The crystal class is body-centred cubic.

Explanation:

NOW FOR THE SECOND QUESTION

The density  d=530kg/m3=0.530g/cm3

(∵1kg/m3=10−3g/cm3)

Atomic mass M=6.94g/mol

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

Density  d=a^3NA​ZM​

0.530=a3×6.023×10232×6.94​

a3=4.34×10−23

The edge length a=3.52×10−8cm=352×10−12m=352pm

(∵1m=100cm and 1pm=10−12m)

HOPR THIS HELPS YOU\