JEE Questions for Chemistry The Solid State Quiz 1 - MCQExams.com

Iodine, sulphur and phosphorus exists as I₂, S₆ and P₄ respectively. Silicion does exist as covalent crystal in the solid state, because in silicon, constituent particles are bonded together by covalent bons.

Glass is a supercooled liquid . Supercooling is a process of lowering the temperature of a liquid or a gas below its freezing point without it becoming a solid.

The body-centered cubic (bcc) has a coordination number of 8 and contains 2 atoms per unit cell.

For Rhombohedral lattice system . The unit cell is a rhombohedron , this is a primitive unit cell with parameters a = b = c ,α = β = γ ≠ 90^o.

In geometry, truncated octahedron is an archimedean solid. It has 14 faces (8 regular hexagonal and 6 square), 36 edges and 24 vertices. Since each of its faces has point symmetry the truncated octahedron is a zonohedron. It is also the goldberg polyhedron Give (1, 1), containing square and hexagonal faces.

If FCC is made of elements A and B,

Number of atoms in FCC = atoms of A at corner + atoms of B at face

                                          = 8 × 1/8 + 6 × 1/2

                                          = 1 + 3

                                          = 4

∴ The formula of the compound is AB₃

Each Zn²⁺ ion is coordinated tetrahedral to 4 S^2- nearest neighbors. So the coordination number is 4.

In the given example, the system forms octahedral void, hence the  coordination number is 6.

Zinc blende (ZnS) crystals are composed of equal number Zn²⁺ and S^2- , which suggests that, it has tetrahedral arrangement and S^2- ions is this is fcc while Zn²⁺ ions occupy alternater tetrahedral roids.

For ionic solids, radius ratio lies between 0.732-1 , when the co-ordination number is 8.

There are four diagonals in a cube. As there are two atoms on each diagonal, there are total of 4 × 2 = 8 atoms on the diagonals. These 8 atoms are within the body of the cubic unit cell and are not shared by other units.

The contribution of 8 corner atoms, 8 × 1/8 =1 atom

Therefore, total number of atoms in the unit cell = 8 + 1= 9 atoms.

In Cesium chloride crystal lattice (CsCl), Each Cs⁺ is surrounded by 8Cl^– (So the Cs⁺ coordination number is 8)at the corners of each cube. Each Cl^– is also surrounded by 8Cs⁺ at the corners of a cube, so the Cl^– has coordination is 8.

The body-centered cubic (bcc) has a coordination number of 8 and contains 2 atoms per unit cell.

Zinc blende (ZnS) crystals are composed of equal number Zn²⁺ and S^2- , which suggests that, it has tetrahedral arrangement and S^2- ions is this is fcc while Zn²⁺ ions occupy alternater tetrahedral roids. Hence the coordination number of S^2- is 4.