Solid State Test - 11

Quratz glass is an amorphous solid with isotropic properties .Therfore it would exhibit same value of refractive index when measured in any of the directions.

Amorphous solids are isotropic because they show thermal and optical properties, same in all directions.

A regular arrangement of constituent particles observed over a long distance in the crystal lattice .

Iodine molecule is a nonpolar covalent molecule . Thes molecules are electrically symmetical and have no dipole moment. The molecules are in a crystal lattice of iodine, therefore, attracted together by weak ' London forces '

Diamonds are resulted by the formation of strong directional 'covalent bonds' between the adjacent atoms throughout the crystal. It is the hardest substance on Earth which has a high level of melting point. It has a structure of tetrahedral.

It is used to sharpen hard tools, in the making of dyes and in manufacture of tungsten filaments due to its high melting point.

Ionic solids in their molten state behave as an electrolytic conductor / electrolyte, therefore the statement at (i) is not true charecteristic of ionic solids.

In graphite one carbon atom is attached to three other carbon atoms. One electron of carbon remains free. Due to this free valence electron graphite is an electrical conductor.

Each lattice point in pure crystal is occupied by either an atom or molecule or ion which are joined together by a straight line to bring out the geometry of pure crystal constituents which are arranged in fixed stoichiometric ratio.

Graphite is a covalent or Network solid , therefore it cannot be grouped as an ionic solid.