Wax is an example of

In a compound, atoms of element Y form ccp lattice and those of element X occupy 2/3^rd of tetrahedral voids. The formula of the compound will be

In a solid lattice, the cation has left a lattice site and is located at an interstitial position. The lattice defect is

In a face-centered cubic lattice, atom A occupies the corner positions and atom B occupies the face centre positions.If one atom of B is missing from one of the face centred points,the formula of the compound is

In a solid 'AB' having NaCl structure, 'A' atoms occupy the corners of the cubic unit cell.If all the face-centred atoms along one of the axes are removed,then the resultant stoichiometry of the solid is

Sodium metal crystallize in a body-centred cubic lattice with a unit cell edge of 4.29\(\overset{0}{A}\).The radius of sodium metal is approximately

If a is the length of side of a cube,the distance between the body-centred atom and one corner atom in the will be

Edge length of a cube is 400pm,its body diagonal would be

If the edge length of a NaH unit cell is 488pm,what is the length of Na-H bond if it crystallises in the fcc structure?

Which of the following is an amorphous solid?

Why is FeO(s) not formed in stoichiometric composition?

Classify the following into ionic, molecular, covalent and metallic crystals.
Bronze, Dry ice, Nitre and Diamond

Write the coordination number of each ion in the folloeing crystals:
(i) NaCl
(ii) CsCl
(iii) ZnS
(iv)CaF₂
(v) Na₂O

How can you convert NaCl structure into CsCl structure and vice versa? 

Define the following terms in relation to crystalline solids:
(i) Unit cell
(ii) Coordination number
Give one example in each case.

Explain the following terms with suitable examples of each:
(i) Freeomagnetism
(ii) Antiferromagnetism.

Calculate the packing efficiency in case of a metal crystal for simple cubic lattice.

An alloy is of gold and cadmium crystallises with a cubic structure in which gold atoms occupy the corners and cadmium atoms fit into the face centre. Assign formula for this alloy.

An element occurs in bcc structure. It has a cell edge length of 250 pm. Calculate the molar mass if its densuty is 8.0 g cm^-3. Also calculate the radius of an atom of this element.

Copper crystallises with face-centred cubic unit cell. If the radius of copper atom is 127.8 pm, calculate the density of copper metal.(Atomic mass of Cu = 63.55 u and Avogadro's number, N_A = 6.02\(\times \) 10²³ MOL^-1)

Explain the following properties given suitable examples:
(i) Ferromagnetism;
(ii) Paramagnetism;
(iii) Ferrimagnetism.

The density of copper metal is 8.95 g cm^-3. If the radius of copper atom is 127.8 pm, is the copper unit cell a simple cubic, a body-centred cubic or a face-centred cubic structure?
(Give: At. mass of Cu = 63.54 g mol^-1 and N_A = 6.02\(\times \)10²³ mol^-1).

Calculate the efficiency of packing in case of a metal crystal for
(a) simple cubic,
(b) body-centred cubic, and
(c) face-centred cubic (with the assumption that atoms are touching each other).

Certain crystals, when subjected to a mechanical stress get deformed and produce electricity due to displacement of ions. The electricity thus produced is called piezoelectricity and such crystals are called piezoelectric crystals. On the other hand, when such crystals are subjected to an electric field, the atomic displacements are produced which cause mechanical distortion in the crystals. These unique properties of piezoelectric crystals find several applications. Now, answer the following questions:
(i) How do piezoelectric crystals behave?
(ii) Mention one application of piezoelectric crystals.
(iii) Just like certain crystals piezoelectric crystals perform better even under mechanical stress and show' various application, how do you behave under stress? What values we can adopt from even these non-living crystals?

Compounds having general molecular formula  \(AFe_{ 2 }O_{ 4 }\) are called ferrites and posses spinel type structures. Some common examples are \(MgFe_{ 2 }O_{ 4 }\)  and \(ZnFe_{ 2 }O_{ 4 }\) They may be thought of being formed by replacing \(Fe^{ 2+ }\) ions present in \(Fe_{ 3 }O_{ 4 }\) by bivalent cations such as \(Mg^{ 2+ },Zn^{ 2+ }\) ions etc. Now answer the following questions :
(i) What types of materials are ferrites?
(ii) What are the main uses of ferrites?