How many octahedral and tetrahedral holes are present per unit cell in a face centred cubic arrangement of atoms?

(1) 8,4

(2) 1.2

(3) 4.8

(4) 2.1

Choose the correct matching sequence from the possibilities given

An element (atomic mass = 100 g mole) having BCC structure has unit cell edge 400 $A^o$. The density of the element is (number of atom bcc(z)=2)

1. 2.144g/cm³
2. 5.2g/cm³
3. 7.289g/cm³
4. 10.376g/cm³

The appearance of color in solid alkali metal halides is generally due to:-

1. Frankel Defect

2. Interstitial Defect

3. F-Centres

4. Schottky Defect

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

1. 250 pm

2. 200 pm

3. 300 pm

4. 335 pm

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

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

Given that the length of the side of a unit cell of lithium is 351 pm, its atomic radius will be -

[Li forms Bcc crystals]

1. 153.69 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) 0.668 g cm^–3

(2) 0.585 g cm²

(3) 1.23 g cm^–3

(4) None