Question

Match the following:

Unit cell	Definition
(a) Primitive	(i) Contains one constituent at its body-centre other than corners
(b) End-centred	(ii) constituents only at the corners
(c) Face-centred	(iii) constituents at the centre of any two opposite faces other than corners
(d) Body- centred	(iv) constitutents at the centre of each face other than corners
	(v) constitutents only at the centre of cell

• A. (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
• B. (a)-(ii), (b)-(iii), (c)-(iv), (d)-(v)
• C. (a)-(v), (b)-(ii), (c)-(iv), (d)-(i)
• D. (a)-(ii), (b)-(v), (c)-(iv), (d)-(i)

Answer 1

The correct option is A (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)

Primitive unit cell:
In promitive constituent particles are present only on the corner positions of a unit cell.

End-Centred unit cell:
In end-centred, one constituent particle is present at the centre of any two opposite faces besides the ones present at its corners.


Face-centred unit cell:
In face-centred, constituent particles are present at the corners and at the centre of each face of the unit cell.

Body-centred unit cell:
Body-centred unit cell contains one constituent particle (atom, molecule or ion) at its body-centre besides the ones at its corners.

Thus, option (a) is correct.