Solid State

How many unit cells are divided equally in a face-centred cubic lattice?

• 2

• 4

• 6

• 8

A crystalline solid:

• changes abruptly from solid to liquid when heated.

• has no definite melting point.

• undergoes deformation of its geometry easily

• has irregular 3-dimensional arrangements.

In a simple cubic, body-centered cubic and face-centered cubic structure, the ratio of the number of atoms present is respectively.

• 4:2:3

• 8:1:6

• 1:2:4

• 4:2:1

Na and Mg crystallize in crystals of bcc and fcc form respectively and then the amount of Na and Mg atoms present in their respective crystal unit cells is:

• 4 and 2

• 9 and 14

• 14 and 9

• 2 and 4

For orthorhombic system axial ratios are a b c and the axial angles are:

• α = β = γ ≠ 90

• α ≠ β ≠ γ ≠ 90

• α = β = γ = 90

• α ≠ β ≠ γ = 90

Copper crystalline in FCC with a unit cell length of 361pm. What is the radius of a copper atom?

• 127pm

• 123pm

• 181pm

• 167pm

Schottky defect in crystal is observed when

• The ion leaves its normal position and occupies an interstitial location

• unequal number of cation and anions are missing from the lattice

• density of the crystal increases.

• an equal number of cations and anions are missing from the lattice.

Each of the following solids show, the Frenkel defect except

• ZnS

• AgBr

• AgI

• KCl

A metal crystallises with a face centred cubic lattice.The edge of the unit cell is 408 pm.The diameter of the metal is:

• 288 pm

• 408 pm

• 144 pm

• 204 pm

A solid X⁺ Y^- has a bcc structure . If the distance of closest approach between the two ions is 173 pm, the edge length of the cell is :

• 200 pm

• 142.2 pm

• Under root 2 pm

• 178 pm