1. Explain the following termswith suitable examples:
(i) Schottky defect (ii) Frenkeldefect (iii) Interstitials and (iv) F-centres.
2. Aluminium crystallises in acubic close-packed structure. Its metallic radius is 125 pm.
(i) What is the length of the side ofthe unit cell?
(ii) How many unit cells are there in1.00 cm3 of aluminium?
3.If NaCl is doped with 10–3 mol % of SrCl2, what is the concentrationof cation vacancies?
4. Explain the following withsuitable examples:
(i) Ferromagnetism (ii) Paramagnetism (iii) Ferrimagnetism (iv) Antiferromagnetism
(v) 12-16 and 13-15 group compounds
5. Silver crystallises in fcclattice. If edge length of the cell is 4.07 × 10–8 cm and density is10.5 g cm–3,
calculatethe atomic mass of silver.
6. A cubic solid is made of twoelements P and Q. Atoms of Q are at the corners of the cube and P at the
body-centre. What is the formula of the compound?What are the coordination numbers of P and Q?
7. Niobium crystallises in body-centred cubic structure. If density is 8.55 g cm–3, calculate atomic radius of niobium using its atomic mass 93 u.
8. How can you determine the atomic mass of an unknown metal if you know its density and the dimension of its unit cell? Explain
9. What makes a glass different from a solid such as quartz? Under what conditions could quartz be converted into glass?
10. Non-stoichiometric cuprousoxide, Cu2O can be prepared in laboratory. In this oxide, copper tooxygen ratio is slightly less than 2:1.Can you account for the fact that this substance is a p-type semiconductor?