A compound is formed by elements A and B. This crystallises in the cubic structure where the A atoms are at the corers of the cube and B atoms are at the body centres. The simplest formula of the compound is

• AB

• A₆B

• A₈B₄

• AB₆

A compound of 'A' and 'B' crystallises in a cubic lattice in which 'A' atoms occupy the lattice points at the corners of the cube. The 'B' atoms occupy the centre of each face of the cube. The probable empirical formula of the compound is

• AB₂

• A₃B

• AB

• AB₃

In face centred cubic lattice, a unit cell is shared equally by how many unit cells?

• 6

• 4

• 2

• 8

Volume occupied by single CsCl ion pair in a crystal is 7.014 × 10^-23 cm³. The smallest Cs-Cs internuclear distance is equal to length of the side of the cube corresponding to volume of one CsCl ion pair. The smallest Cs to Cs internuclear distance is nearly 

• 4.4 Å

• 4.3 Å

• 4 Å

• 4.5 Å

Metallic lustre is due to

• high density of metals

• high polish on the surface of metals

• reflection of light by mobile electrons

• chemical inertness of metals

The unit cell with crystallographic dimensions, a≠b≠c,α=γ=90 and β≠ 90 is

• triclinic

• monoclinic

• orthorhombic

• tetragonal

Sodium metal crystallises in bee lattice with edge length of 4.29 Å. The radius of sodium atom is

• 2.857 Å

• 1.601 Å

• 2.145 Å

• 1.857 Å

A crystalline sold XY₃ has ccp arrangement for its element Y. X occupies

• 66% of tetrahedral voids

• 33% of tetrahedral voids

• 66% of octahedral voids

• 33% of octahedral voids

109.

The contribution of particle at the edge centre to a particular unit cell is

• $\frac{1}{2}$

• $\frac{1}{4}$

• 1

• $\frac{1}{8}$

Schottky defect in a crystal is observed, when

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

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

• an ion leaves its normal site and occupies an interstitial site

• no ion is missing from its lattice site