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

Fraction of total volume occupied by atoms in a simple cube is

(1) $\frac{\pi }{2}$

(2) $\frac{\sqrt{3}\pi }{8}$

(3) $\frac{\sqrt{2}\pi }{6}$

(4) $\frac{\pi }{6}$

With which one of the following elements silicon should be doped so as to give p-type of semiconductor?
(1) Germanium

(2) Arsenic

(3) Selenium

(4) Boron

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

Analysis show that nickel oxide consist of nickel ion with 96% ions having d⁸ configuration and 4% having d⁷ configuration. Which amongst the following best represents the formula of the oxide.

(1) Ni_1.02O_1.00

(2) Ni_0.96O_1.00

(3) Ni_0.96O_0.98

(4) Ni_0.98O_1.00

A compound forms hcp structure. The total number of voids in 0.5 mol will be- 

1. 9.033$\times$10²³

2. 6.011$\times$10²³

3. 5.023$\times$10²³

4. 7.033$\times$10²³

In a metal oxide, the oxide ions are arranged in hexagonal close packing and metal ions occupy two third of the octahedral voids. The formula of the oxide is : 

1. MO

2. M₂O₃

3. MO₂

4. M₂O

Packing fraction of simple cubic crystal lattice is 

1. 38%

2. 74%

3. 68%

4. 52.4%

Ice crystallizes in a hexagonal lattice having the volume of the unit cell as $132\times {10}^{-24}$ $c{m}^3$. If the density is 0.92 g/cm³ at a given temperature, then the number of H₂O molecules per unit cell is : 

1. 1

2. 2

3. 3

4. 4

Sodium metal crystallizes in bcc lattice with cell edge $=4.29 \stackrel{0}{A}$. The radius of sodium atom will be-

(1) 1.50 $\stackrel{0}{A}$                                                 

(2) 1.86  $\stackrel{0}{A}$

(3) 2.80 $\stackrel{0}{A}$                                               

(4) None of these