Questions on superconducting metals & X-ray crystallography

(b) The diagram below shows representations of three different types of cubic cells labelled I, II and III.

Identify each of the three types of cubic cell and deduce the number of atoms in each type of unit cell and the coordination number of each atom in the cell.

2. Copper has a face-centred cubic structure. The side of one of the unit cells has been found by X-ray diffraction to be equal to 3.613 x 10^-10 m . Knowing that the atomic mass of copper is 63.55 g mol^-1 calculate the density of copper to three significant figures.

3. The graph below shows how the resistance of two different materials (labelled I and II) changes with temperature.

(a) Identify the type of superconductor shown by graph II.

(b) Explain the significance of temperature x

(c) Explain why the superconductor responsible for graph II has zero resistance at very low temperatures.

(d) Deduce what type of material is responsible for producing graph I.

4. Like copper, gold also packs with a face-centred cubic structure. Face-centred cubic structure packing occupies 74% of the available space. The density of gold is 19.32 g cm^-3.

(a) Determine the metallic radius of a gold atom.

(b) Compare the metallic radius of gold with the covalent radius of gold given in Section 9 of the data booklet.

Download the  Superconducting metals & X-ray crystallography questions to give to your students.