Distinguish between Face-centred and end-centred unit cells.
|Face-centred unit cell||End-centred unit cell|
|A Face-centred unit cell the constituent particles are present at the corners and one at the centre of each face.||An End-centred unit cell contains particles at the corners and one at the centre of any two opposite faces.|
|Total no of particles in a face centered unit cell= 4||Total no. of particles in an end centered unit cell = 2|
An element with molar mass 27 g mol−1 forms a cubic unit cell with edge length 4.05 ✕ 10−8 cm. If its density is 2.7 g cm−3, what is the nature of the cubic unit cell?
An element with molar mass 2.7 × 10-2 kg mol-1 forms a cubic unit cell with edge length 405 pm. If its density is 2.7 × 103 kg m−3, what is the nature of the cubic unit cell?
An element crystallises in a b.c.c lattice with cell edge of 500 pm. The density of the element is 7.5g cm-3. How many atoms are present in 300 g of the element?