# Lithium has a BCC structure. Its density is 530 kgm-3 and its atomic mass is 6.94 g mol-1. Calculate the edge length of a unit cell of Lithium metal (NA = 6.02 x 1023 mol-1)

By K Balaji|Updated : November 4th, 2022

(a) 352 pm

(b) 527 pm

(c) 264 pm

(d) 154 pm

Lithium has a BCC structure. Its density is 530 kgm-3 and its atomic mass is 6.94 g mol-1. The edge length of a unit cell of Lithium metal is 352 pm.

d = (z x M)/ (a3 x NA)

z is 2 here since this is BCC.

Now substituting values we get

0.53 g/cm3 = (2 x 6.94) g/mol/ (a3 x 6.02 x 1023) mol-1

a3 = 43.5 x 10-24 cm3

By taking cube roots we get

a = 3.52 x 10-8 cm

On simplifying we get

a = 352 pm

### Properties of Lithium

• In several reactions involving both organic and inorganic reactants, lithium plays an active role. It forms monoxide and peroxide when it interacts with oxygen.
• Water and metallic lithium interact quite violently.
• This metal has a high specific heat, or calorific capacity, which is one of its notable characteristics. Other characteristics include its wide range of temperatures in the liquid state and strong thermal conductivity.
• Both its density and viscosity are quite low.
• This metal's metallic form is insoluble in hydrocarbons but soluble in short-chain aliphatic amines like ethylamine.

Summary:-

## Lithium has a BCC structure. Its density is 530 kgm-3 and its atomic mass is 6.94 g mol-1. Calculate the edge length of a unit cell of Lithium metal (NA = 6.02 x 1023 mol-1) (a) 352 pm (b) 527 pm (c) 264 pm (d) 154 pm

Lithium has a BCC structure with density 530 kgm-3 and atomic mass is 6.94 g mol-1. 352 pm is the edge length of a unit cell of Lithium metal. Lithium is a chemical element which occurs first in the periodic table.

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