Metals have conductivity of the order of (ohm-1 m-1):-
1. 1012
2. 108
3. 102
4. 10-6
What type of crystal defects is indicated in the diagram given below?
1. Frenkel and Schottky defects
2. Schottky defect
3. Interstitial defect
4. Frenkel defect
Which arrangement of electrons leads to anti-ferromagnetism?
1.
2.
3. Both (1) and (2)
4. None of the above.
Among the following types of voids. which one is the largest void:-
1. Triangular system
2. Tetragonal system
3. Monoclinic system
4. Octahedral
In a compound, atoms of element Y form ccp lattice, and those of element X occupy 2/3rd of tetrahedral voids. The formula of the compound will be :-
1. X3Y4
2. X4Y3
3. X2Y3
4. X2Y
A spinel is an important class of oxides consisting of two types of metal ions with the oxide ions arranged in ccp layers. The normal spinel has 1/8th of the tetrahedral void occupied by one type of metal and one half of the octahedral voids occupied by another type of metal ions. Such a spinel is formed by Zn2+, Al3+ and O2- with Zn2+ in tetrahedral void. Give the simplest formula of the spinel.
1. ZnAl2O4
2. ZnAl2O3
3. ZnAlO
4. None of these
The density of KCl is 1.9893 g cm-3 and the length of a side unit cell is 6.29082 Å as determined by X-ray diffraction. The value of Avogadro’s number
calculated from this data is:-
1. 6.017 x 1023
2. 6.023 x 1022
3. 7.03 x 1023
4. 6.01 x 1019
Copper metal has a face-centred cubic structure with the unit cell length equal to 0.361nm. Picturing copper ions in contact along the face diagonal. The apparent radius of a copper ion is-
1. 0.128
2. 1.42
3. 3.22
4. 4.22
Compute the percentage void space per unit volume of unit cell in zinc fluoride structure.
1. 15.03%
2. 22.18%
3. 18.23%
4. 25.07%
Oxygen atoms form fcc unit cells with 'A' atoms occupying all tetrahedral voids and 'B' atoms occupying all octahedral voids. If atoms are removed from two of the body diagonals then the formula of the resultant compound formed is:
1. A4B4O7
2. A8B6O7
3. A8B8O7
4. A6B8O6
Frenkel defect is not found in the halides of alkali metals because alkali metals have
1. High electropositivity.
2. High ionic radii.
3. High reactivity.
4. Ability to occupy interstitial sites.
In a face centred cubic lattice, atom A occupies the corner positions and atom B occupies the face
centre positions. If one atom of B is missing from one of the face centred points, the formula of the compound is
1.AB2
2.A2B3
3.A2B5
4.A2B
A metallic element crystallizes into a lattice containing a sequence of layers of ABABAB ............ Any packing of spheres leaves out voids in the lattice. The percentage by volume of empty space of this is
(1) 26%
(2) 21%
(3) 18%
(4) 16 %
CsBr has a (bcc) arrangement and its unit cell edge length is 400 pm. Calculate the interionic distance in CsBr.
(1) 346.4 pm
(2) 643 pm
(3) 66.31 pm
(4) 431.5 pm
The diffraction of barium with X-radiation of wavelength 2.29Å gives a first – order reflection at 30°. What is the distance between the diffracted planes.
(1) 3.29 Å
(2) 4.39 Å
(3) 2.29 Å
(4) 6.29 Å
Lithium has a bcc structure. Its density is 530 kg m-3 and its atomic mass is 6.94 gmol-1.
The edge length of a unit cell of lithium metal is -
(NA=6.02 x1023 mol-1)
1. 352 pm
2. 527 pm
3. 264 pm
4. 154 pm
A given metal crystallises out with a cubic structure having edge length of 361 pm. If
there are four metal atoms in one unit cell, what is the radius of one atom ?
1. 40 pm
2. 127 pm
3. 80 pm
4. 108 pm
The correct statement regarding defects in the crystalline solid is
1. Schottky defects have no effect on the density of crystalline solids
2. Frenkel defects decreases the density of crystalline solids
3. Frenkel defcct is a dislocation defect
4. Frenkel defect is found in halides of alkaline metals
Lithium metal crystallises in a body centred cubic crystal. If the length of the side of the
unit cell of lithium is 351 pm, the atomic radius of the lithium will be
1. 240.8 pm
2. 151.8 pm
3. 75.5 pm
4. 300.5 pm
An element (atomic mass = 100 g/mole) having a BCC structure has a unit cell edge of 400 pm. The density of the element is :
1. 2.14 g/cm3
2. 5.20 g/cm3
3. 7.28 g/cm3
4. 10.37 g/cm3