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Given : a = 495 pm

Radius, r = ?

For fee structure,

radius = r \(= \frac{a}{2\sqrt{2}} = \frac{495}{2 \times \sqrt{2}}\) = 175 cm.

Radius of Cu atom = 175 pm.

1. 74% 

2. Schottky 

3. density 

4. Schottky defect 

5. Frenkel defect 

6. metal excess defect 

7. Colourless, yellow 

8. Metal deficiency 

9. Piezoelectricity 

10. intrinsic or thermodynamic

The number of atoms in fee unit cell is 4 .

Option : (c) K₂SO₄

The coordination number of zinc sulphide is 4 .

6 is the coordination number of NaCl.

(c) Trigonal planar

3 is the coordination number of B₂O₃ .

Correct answer is: (C) 60 to 80% SiO₂, 10 to 25% B₂O₃ and remaining amount of Al₂O₃

(a) Both A and R are correct and R is the correct explanation of A

Correct answer is: (B) the unit cell having crystal parameters, a = b \(\neq\) c, \(\alpha\) = \(\beta\) = 90\(^\circ\) and \(\gamma\) = 120\(^\circ\) is hexagonal

Correct answer is: (B) monoclinic

Correct answer is:  (A) \(\cfrac{4m}{a^3}\)
\(\therefore\) Mass of fcc unit cell of silver = 4m

(\(\therefore\) fcc type unit cell contains total 4 atoms)

Edge length of fcc unit cell = a

Volume of fcc unit cell = a³

Density of silver (Ag) =\(\cfrac{Mass\,of\,fcc \,unit \,cell}{Volume\,of\,fcc\, unit\,cell}\)

\(\therefore\) Density of silver (Ag) = \(\cfrac{4m}{a^3}\)

(i) Ferrimagnetism

(ii) Schottky defect

The most common examples of the intrinsic semiconductors are silicon and germanium.

n-type semiconductors are those substances which have impurity with extra electrons. 

Example: When silicon doped with group 15^th element, n-type semiconductor isobtained.

When a crystal of LiCl is present in excess of Lithium, the lithium atom loses an e^- to from Li⁺ ions. The released e^- diffuse into the crystal and occupies the anionic sites (F-centre). These e^- imparts the pink colour to the crystal.

This is due to F-centres.

(i) Schottky defect.

(ii) Decreases

(iii) Alkali metal halides/ionic substances having almost similar size of cations and anions (NaCl/KCl).

Correct answer is: (D) Molecular crystal

The correct option is (b) Frenkel defect is a dislocation defect.

The Schottky defect has some effect on the physical properties of solids such as lower density, lower lattice energy or stability etc.

Frenkel defect is usually favoured by a  large difference in the sizes of cations and anions. Cations are small in size than anions.

Frenkel defect is a dislocation defect. A cation moves to another position between two layers.

Trapping of electrons in the lattice leads to the formation of F-centers.

When colourless ZnO is strongly heated, the metal atoms are deposited on crystal surface and anions O^2- migrate to the surface producing vacancies at anion lattice points.

These anions combine with Zn atoms forming

ZnO and release electrons.

Zn + O^2- \(\rightarrow\) ZnO + 2^e-

These released electrons diffuse into the crystal and occupy vacant sites of anions and produce F- centres. Due to these colour centres, ZnO turns yellow.

Let a small quantity of phosphorus be doped into pure silicon.

(a) Tetrahedral voids

(b) Octahedral void

Ability of a substance to produce electric current on application of mechanical stress. 

8 (at corner ) +1 (at body centre)

It is the percentage of total space occupied by constituent particles (atoms, molecules or ions) in a unit cell.

Packing Efficiency = Volume occupied by spheres/Total volume of unit cell x 100%

Packing efficiency of hcp is 74%

(A) The cation at the center of each face is shared by two unit cells. Hence no. of cations= 6 X 1/2 = 3

(B) The anion at each corner is shared by 8 unit cells . the anion at the center is not shared by any other unit cell. Hence no. of anions= 8 X 1/8 + 1 = 2

(C) Since there are 3 cations and 2 anions the simplest formula of the compound is A₃B₂.

The free electrons trapped in the anion vacancies are termed as the F- centers. The solids containing the F-centres are paramagnetic because the electrons occupying the vacant sites are unpaired.

Correct answer is: (C) X₂Z

Correct answer is: (B) AB₄

Number of atoms of A = 6\(\times\cfrac{1}{8}=\cfrac{3}{4}\)

Number of atoms of B = 6 \(\times\cfrac{1}{2}\) = 3

A : B =\(\cfrac{3}{4}\) : 3 = 1 : 4

\(\therefore\) Composition of alloy = AB₄

Covalent solid formed by covalent bonds between neighbouring constituent atoms of non-metallic solid is called a giant solid. 

For example, 

Graphite.

Radius ratio = r⁺ /r^- = 0.414 

OR 140/ rB- = O.414 

 SO r B- = 140/0.414 

 = 338 pm 

Correct answer is: (A) Solids are always crystalline in nature.

Correct answer is: (B) an integer

The defects which result from improper orientation of planes with respect to one-another in the crystal are called dislocations. 

The replacement of one Ag⁺ ion with Cd⁺ ion necessitates the removal of other Ag⁺ ion from the lattice to maintain the electrical neutrality of the crystal. But in case of NaCl, Na⁺ and Ag⁺ both are monovalent. 

Correct answer is: (A) Schottky defect

The gap between constituent particles is known as voids.

Correct answer is: (D) All of these

(i) Frenkeldefect 

(ii) Schottky defect

Correct answer is: (C) do not undergo clean cleavage when cut with knife

1. The constituent particles in amorphous solids are arranged randomly. 

2. They have short range ordered structure. 

3. Amorphous solids are called supercooled liquids having very high viscosity. 

4. They do not have sharp melting points and they melt gradually over a temperature interval.

5. Amorphous substances appear like solids but they do not have perfectly ordered crystalline structure, hence they are not real solids. Therefore they are pseudo solids. 

6. They are isotropic and exhibit the same magnitude of any property in every direction.

Isomorphism : A phenomenon in which two or more crystalline substances show same crystalline structure is called isomorphism and the crystals are said to be isomorphous. 

For example, 

NaNO₃ and CaCO₃. 

They have atomic ratios 1 : 1 : 3.

8x1/8 + 6x1/2=4(8 corners & 6 faces)

Isomorphous : When two or more crystalline substances have the same crystalline structure, they are said to be isomorphous. 

For example, 

NaF and MgO₃, NaNO₃ and CaCO₃.

Material will be electrically neutral.

The no of atoms to which central atom is touching

Substances which are attracted by external magnetic field due to presence of unpaired electrons .

Doping is defined as addition of impurities from outside to a crystal.