Question 1 :
The CsCl structure is observed in alkali halides only when the radius of the cation is sufficiently large to keep its eight nearest-neighbour anions from touching. What minimum value of $r_{+}/ r_{-}$ is needed to prevent this contact?

Question 2 :
Which of the following arrangements correctly represents hexagonal and cubic close packed structure respectively?

Question 3 :
How many unit cells are present in $39\ g$ of potassium that crystallises in body-centred cubic structure?

Question 4 :
How many unit cells are present in a cubic shaped ideal crystal of NaCl of mass 1.0 g?

Question 5 :
$C_{60}$ (bucky ball) is cubic closest packed (face Centred cubic) in its crystalline form. If you insert potassium atoms into all the tetrahedral and octahedral holes of the $C_{60}$ structure, the formula would become $K_xC_{60}$. What is the value of $x$? 

Question 6 :
The anions $(A)$ form hexagonal closest packing and atoms $(M)$ occupy only two-thirds of octahedral voids in it; then the general formula of the compound is:

Question 7 :
An element has a body centered cubic (bcc) structure with a cell edge of $288 pm$. The atomic radius is

Question 8 :
If the anions A form hexagonal closest packing and cations C occupy only $\dfrac 23$rd of the octahedral voids in it, then the general formula of the compound is :

Question 10 :
The total volume of atoms present in a $fcc$ unit cell of a metal with radius $r$ is:

Question 11 :
Three elements A,B, and C crystallize into a cubic solid lattice. Atoms A occupy the corners, B atoms, the cube centres and C atoms, the edge.The formula of the compound is _________.

Question 12 :
The total number of atoms per unit cell of bcc is:<br/>

Question 13 :
In a compound, atoms of element Y form ccp lattice and those of element X occupy $2/3^rd$ of tetrahedral voids. The formula of the compound will be:

Question 14 :
In chromium chloride $(CrCl_3)$, $Cl^-$ ions have cubic close packed arrangement and $Cr^{3+}$ ions are present in the octahedral holes. The fraction of the total number of holes occupied is:

Question 15 :
The contribution of particle at the edge centre to a particular unit cell is :

Question 18 :
Which of the following statement is not true about the voids?

Question 19 :
The number of atoms in 100 g of an F.C.C. crystal with density $d = 10 g cm^{-3}$ and cell edge as 200 pm is equal to:

Question 21 :
If an atom is present in the centre of the cube, the participation of that atom per unit cell is:

Question 24 :
Example of unit cell with crystallographic dimensions $a\neq b \neq c, \alpha = \gamma = 90^{\circ}, \beta \neq 90^{\circ}$ is.

Question 25 :
How many molecules are there in the unit cell of sodium chloride?

Question 26 :
For bcc structure, the coordination number and packing are ______&#160; respectively.

Question 27 :
How many kinds of space lattices are possible in a crystal?<br/>

Question 29 :
The number of atoms per unit cell in a simple cube, face-centred cube and body-centred cube are respectively.

Question 30 :
In a fcc arrangement of A and B atoms where A atoms are at&#160;the corners of the unit cell and B atoms at the face centres,&#160;one of the A atom is missing from one corner in each unit&#160;cell. What is the simplest formula of compound?

Question 32 :
At what angles for the first order diffraction, spacing between two planes, respectively, are $\lambda$ and $\dfrac{\lambda }{2}$?

Question 35 :
Assertion: Space or crystal lattice differ in symmetry of the arrangement of points. Reason: $n\lambda = 2d\sin \theta$, is known as Braggs equation.

Question 36 :
How many unit cells are present in a cube-shaped ideal crystal of NaCl of mass 1.00 kg?&#160;<div>[Atomic masses of Na and Cl are 23 g/mol and 35.5 g/mol respectively.]<br/></div>

Question 37 :
A compound formed by elements $A$ and $B$ crystallises in the cubic structure where $A$ atoms are at the corners of a cube and $B$ atoms are at the face centres. The formula of the compound is

Question 38 :
In the Bragg's equation for diffraction of X-rays, $n$ represents for

Question 39 :
A substance $A_xB_y$ crystallizes in a face centred cubic (fcc) lattice in which atoms $A$ occupy each corner of the&#160;cube and atoms $B$ occupy the centres of each face of the&#160;cube. Identify the correct composition of the substance $A_xB_y$.

Question 40 :
The unit cell with crystallographic dimensions, $a\ne b\ne c$, $\alpha=\gamma=90$ and $\beta\ne 90$ is called :

Question 41 :
The intermetallic compound $LiAg$ crystallizes in the cubic lattice in which both lithium and silver have a coordination number of eight. The crystal class is :

Question 42 :
A substance $A_{x}B_{y}$ crystallizes in an f.c.c. lattice in which atoms of $A$ occupy each corner of the cube and atoms of $B$ occupy the centres of each face of the cube. Identify the correct composition of the substance $A_{x}B_{y}$.

Question 43 :
If a fcc&#160;arrangement of A and B atoms, where A atoms are at the corner of the unit cell and B atoms at the face centres, one of the A atom is missing from one corner&#160;in each unit cell. What is the simplest formula of compound?

Question 44 :
The number of unit cells in $58.5\ g$ of $\text{NaCl}$ is :

Question 46 :
Match the column I having type of lattice point and its contribution to one unit cell in column II and mark appropriate choice.<br><table class="wysiwyg-table"><tbody><tr><td><br></td><td>Column I<br>(Lattice point)</td><td><br></td><td>column II<br>(Contribution to one unit cell)</td></tr><tr><td>(A)</td><td>Corner</td><td>(i)</td><td>1</td></tr><tr><td>(B)</td><td>Edge</td><td>(ii)</td><td>1/8</td></tr><tr><td>(C)</td><td>Face Cenre</td><td>(iii)</td><td>1/4</td></tr><tr><td>(D)</td><td>Body centre</td><td>(iv)</td><td>1/2</td></tr></tbody></table><blockquote><blockquote><blockquote><br></blockquote></blockquote></blockquote>

Question 47 :
Gold crystallises in fcc centred cubic structure. If atomic mass of gold is $197\ g \ mol^{-1}$, the mass of the unit cell of gold will be:

Question 48 :
A cubic unit cell contains manganese ions at the corners and fluoride ions at the centre of each edge.&#160;What is the co-ordination number of the Mn ion ?

Question 49 :
A solid melts slightly above $273$ K and is a poor&#160;conductor of heat and electricity. To which of&#160;the following categories does it belong?

Question 50 :
The second order Bragg diffraction of X-rays with $\lambda =&#160;1.00 \mathring A$&#160;from a set of parallel planes in a&#160;metal occurs at an angle of $60^o$. The distance between the scattering planes in the crystal is (in $\mathring A$) :