Preterm 1

The relationship between the atomic radius (r) and edge length (a) of a simple, fcc, bcc cubic unit cell will be respectively

• $\frac{a}{2}$ $\frac{\sqrt{2}a}{4}$ $\frac{\sqrt{3}a}{4}$

• $\frac{a}{2}$ $\frac{\sqrt{3}a}{4}$ $\frac{\sqrt{2}a}{4}$

• $\frac{\sqrt{2}a}{4}$ $\frac{\sqrt{3}a}{4}$ $\frac{a}{2}$

• $\frac{\sqrt{3}a}{4}$ $\frac{a}{2}$ $\frac{\sqrt{3}a}{4}$

The ability of crystalline solids to change values of physical properties when measured in different directions is called _______.

• polymorphism

• isomorphism

• anisotropy

• isotropy

This type of solid forms a regular repeating

three-dimensional structure called a crystal lattice. What type of solid is this?

• amorphous

• crystalline

• glass

• diamond

Which type of solid typically has the lowest melting point of the four types of crystals?

• Ionic

• Molecular

• Metallic

• Covalent Network

Anionic sites occupied by unpaired electrons are called

• F Centres

• Interstitial Centres

• Cationic Centres

• Anionic Centres

What is contribution of a lattice point present at the body centre towards a unit cell

• 100%

• 50%

• 25%

• 0

What fraction of a sphere present at the face of a unit cell is present in one unit cell

• 1/8

• 1/4

• 1/2

• 1

3. Alkali halides do not show Frenkel defect because

• (a) cations and anions have almost equal size

• (b) there is a large difference in size of cations and anions

• (c) cations and anions have low coordination number

• (d) anions cannot be accommodated in voids

Oxygen is an example of

• diamagnetic substance

• paramagnetic substance

• ferromagnetic substance

• none of these

Molarity is the number of moles of a _______________________________ dissolved per liter of solution.

• M

• solution

• molar

• solute