Packing fraction of simple cubic crystal lattice is 

1. 38%

2. 74%

3. 68%

4. 52.4%

Silver metal crystallises in a cubic closest – packed arrangement with the edge of the unit cell having a length a = 407 pm. What is the radius of silver atom.

(1) 143.9 pm

(2) 15.6 pm

(3) 11.59 pm

(4) 13.61 pm

From the fact that the length of the side of a unit cell of lithium is 351 pm. Calculate its

atomic radius. Lithium forms body-centered cubic crystals.

(1) 152.69 pm

(2) 62.71 pm

(3) 151.98 pm

(4) 54.61 pm

Lithium borohydride $\left(LiB{H}_4\right),$crystallises in an orthorhombic system with 4 molecules per unit cell. The unit cell dimensions are : a = 6.81Å, b= 4.43Å, c=7.17Å. If the molar mass of $LiB{H}_4$ is 21.76 g mol^–1. The density of the crystal is –

(1) 0.67 g cm^–3

(2) 0.58  g cm^–3

(3) 1.23 g cm^–3

(4) 6.68  g cm^–3

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

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

AB crystallizes in a body-centred cubic lattice with edge length a equal to 387 pm. The distance between two oppositely charged ions in the lattice will be : 

1. 250 pm

2. 200 pm

3. 300 pm

4. 335 pm

The vacant space in bcc lattice cell is ;

1. 26%

2. 48%

3. 23%

4. 32%

Copper crystallises in a face-centred cubic lattice with a unit cell length of 361 pm. What

is the radius of copper atom in pm?

1. 128

2. 157

3. 181

4. 108