Solid States

Sloid States
Class:XII / Unit:1

Schottky defect defines imperfection in the lattice structure of

Gas
Liquid
Solid
Plasma

The space lattice of graphite is

Cubic
Tetragonal
Hexagonal
Rhombic

The coordination number in hcp is

6
12
18
24

Which is not correct about the Schottky defects ?

Both cations and anions are missing from their lattice sites without affecting the stoichiometry of the compound
Because of presence of holes the lattice energy decreases
The presence of holes causes the density of the crystal to decrease
The defect increases the electrical conductivity of the solid due to migration of the ions into the holes

If z is the number of atoms in the unit cell that represents the closest packing sequence ..... ABC ABC ...... the number of tetrahedral voids in the unit cell is equal to

Z
Z/2
Z/4
2Z

Coordination Number of Na in NaCl is

6
1
2
4

AB crystallizes in a body centred cubic lattice with edge length 'a' equal to 387 pm. The distance between two oppositively charged ions in the lattice is

300pm
335pm
250pm
200pm

Percentage of free space in a body centred cubic unit cell is

34%
32%
28%
68%

A compound formed by elements X and Y crystallizes in a cubic structure in which atoms X are at the corners of the cube and atoms Y are at the face-centers. The formula of the compound is

X₃Y
XY
XY₂
XY₃

An ionic compound has a unit cell consisting of A ions at the corners of a cube and B ions on the centres of faces of the cube. The empirical formula of the compound would be

AB₃
A₂BY
A₃B
AB