Graphite and diamond are ________.

(a)

Covalent and molecular crystals

(b)

ionic and covalent crystals

(c)

both covalent crystals

(d)

both molecular crystals

In calcium fluoride, having the flurite structure the coordination number of Ca²⁺ ion and F^- Ion are ________.

(a)

4 and 2

(b)

6 and 6

(c)

8 and 4

(d)

4 and 8

The number of carbon atoms per unit cell of diamond is _______.

(a)

8

(b)

6

(c)

1

(d)

4

The ionic radii of A⁺ and B⁻ are 0.98 x 10^-10 m and 1.81 x 10^-10 m. the coordination number of each ion in AB is ________.

(a)

8

(b)

2

(c)

6

(d)

4

Which of the following cannot be regarded as molecular solid?

(a)

Silicon carbide

(b)

AIN

(c)

Diamond

(d)

All the above

Which of the following is characteristic of ionic solids?

(a)

Very low value of electrical conductivity in the molten state

(b)

Brittie nature

(c)

Very strong forces of attractions

(d)

Anisotropic nature

An example of metal deficiency defect _______.

(a)

NaCl

(b)

AgCl

(c)

CsCl

(d)

FeS

What is the relation between diamond and graphite?

(a)

Polymorphous

(b)

Isomer

(c)

Isotope

(d)

Isomorphous

A solid with formula ABC₃ would probably have, _______.

(a)

A at body centre, B at face centres and C at corners of the cube

(b)

A at corners of cube, B at body centre, C at face centre

(c)

A at corners of hexagon, B at centres of the hexagon and C inside the hexagonal unit cell

(d)

A at corner, B at face centre, C at body centre

Amorphous solids have _______.

(a)

Orderly arrangement of atoms

(b)

Long range of melting point

(c)

Anisotropy

(d)

both (a) and (c)

Metal deficiency defect

(1)

KCI

Metal excess defect

(2)

NaCI

Metal deficiency defect

(3)

AgBr

Schottky defect

(4)

FeO

Frenkel defect

(5)

FeO with Fe³⁺