Solid State PYQs

A compound is formed by two elements A and B. The element B forms cubic close packed structure and atoms of A occupy 1/3 of tetrahedral voids. If the formula of the compound is AₓBᵧ, then the value of x + y is:

What fraction of one edge centred octahedral void lies in one unit cell of fcc?

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In a particular point defect, an ionic solid is electrically neutral, even if few of its cations are missing from its unit cells. Reason (R): In an ionic solid, Frenkel defect arises due to dislocation of cation from its lattice site to interstitial site, maintaining overall electrical neutrality. In the light of the above statements, choose the most appropriate answer from the options given below:

Copper crystallises in fcc unit cell with cell edge length 3.608 × 10⁻⁸ cm. The density of copper is 8.92 g cm⁻³. Calculate the atomic mass of copper.

Right option for the number of tetrahedral and octahedral voids in hexagonal primitive unit cell are:

The correct option for the number of body centred unit cells in all 14 types of Bravais lattice unit cells is:

An element has a body centered cubic (bcc) structure with a cell edge of 288 pm. The atomic radius is:

Iron exhibits bcc structure at room temperature. Above 900°C, it transforms to fcc structure. The ratio of density of iron at room temperature to that at 900°C (assuming molar mass and atomic radius of iron remains constant with temperature) is

Which is the incorrect statement?

In calcium fluoride, having the fluorite structure, the coordination numbers for calcium ion $(Ca^{2+})$ and fluoride ion $(F^-)$ are:

The correct statement regarding defects in crystalline solids is:

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

A metal has an fcc lattice. The edge length of the unit cell is $404\,pm$. The density of the metal is $2.72\,g\,cm^{-3}$. The molar mass of the metal is ($N_A=6.02\times10^{23}\,mol^{-1}$)

Which of the following statements about the interstitial compounds is incorrect?

Structure of a mixed oxide is cubic close-packed (c.c.p). The cubic unit cell of mixed oxide is composed of oxide ions. One fourth of the tetrahedral voids are occupied by divalent metal A and the octahedral voids are occupied by a monovalent metal B. The formula of the oxide is:

Sodium has body centred packing. Distance between two nearest atoms is $3.7\,\AA$. The lattice parameter is:

Lithium metal crystallizes in a body centred cubic crystal. If the length of the side of the unit cell of lithium is $351\,pm$, the atomic radius of lithium will be:

Copper crystallizes in a face-centred cubic lattice with a unit cell length of $361\,pm$. What is the radius of copper atom in pm?

If 'a' stands for the edge length of the cubic systems: simple cubic, body centred cubic and face centred cubic, then the ratio of radii of the spheres in these systems will be respectively

Which of the following statements is not correct?

Percentage of free space in a body centred cubic unit cell is

CsBr crystallises in a body centred cubic lattice. The unit cell length is 436.6 pm. Given that the atomic mass of Cs = 133 and that of Br = 80 amu and Avogadro number being 6.02 × 10²³ mol⁻¹, the density of CsBr is:

The appearance of colour in solid alkali metal halides is generally due to:

In a face-centered cubic lattice, a face-centered atom is shared equally by how many unit cells?