Total volume of atoms present in a face-centre cubic unit cell of a metal is (r is atomic radius)
20πr3/3
24πr3/3
12πr3/3
12πr3/3
An ionic compound has a unit cell consisting of A ions at the corners of a cube and B ions on the centres of the faces of the cube. The empirical formula for this compound would be
A2B
AB
AB3
AB3
Lattice energy of an ionic compounds depends upon
Charge on the ion only
Size of the ion only
Packing of ions only
Packing of ions only
Based on lattice energy and other considerations which one of the following alkali metal chlorides is expected to have the highest melting point.
LiCl
NaCl
KCl
KCl
What type of crystal defect is indicated in the diagram below?
Frenkel defect
Frenkel and Schottky defects
Interstitial defect
Interstitial defect
Which type of ‘defect’ has the presence of cations in the interstitial sites?
Metal deficiency defect
Schottky defect
Vacancy defect
Frenkel defect
In a close-packed body-centred cubic lattice of potassium, the correct relation between the atomic radius (r) of potassium and the edge-length (a) of the cube is
r =
r =
r =
r =
Ionic solids with Schottky defect may contain in their structure
cation vacancies only
cation vacancies and interstitial cations
equal number of cation and anion vacancies
anion vacancies and interstitial anions
Suppose the mass of a single Ag-atom is m. Ag metal crystallises in fcc lattice with unit cell of length a. The density of Ag metal in terms of a and m is
The unit cell length of sodium chloride crystal is 564 pm. Its density would be
1.082 g cm-3
2.165 g cm-3
3.247 g cm-3
4.330 g cm-3