Answer
the following questions:
1.
Define unit cell.
2. Give any three
characteristics of ionic crystals.
3. Differentiate
crystalline solids and amorphous solids.
4. Classify the following
solids
a. P4 b.
Brass c. diamond d. NaCl e. Iodine
5. Explain briefly seven
types of unit cell.
6. Distinguish between
hexagonal close packing and cubic close packing.
7. Distinguish tetrahedral
and octahedral voids.
8. What are point defects?
9. Explain Schottky defect.
10. Write short note on
metal excess and metal deficiency defect with an example.
11. Calculate the number of
atoms in a fcc unit cell.
12. Explain AAAA and ABABA
and ABCABC type of three dimensional packing with the help of neat diagram.
13. Why ionic crystals are
hard and brittle?
14. Calculate the percentage
efficiency of packing in case of body centered cubic crystal.
15. What is the two
dimensional coordination number of a molecule in square close packed layer?
16. Experiment shows that
Nickel oxide has the formula Ni0.96 O1.00 . What fraction
of Nickel exists as of Ni2+ and Ni3+ ions?
17. What is meant by the
term “coordination number”? What is the coordination number of atoms in a bcc
structure?
18. An element has bcc
structure with a cell edge of 288 pm. the density of the element is 7.2 gcm-3.
how many atoms are present in 208g of the element.
19. Aluminium crystallizes
in a cubic close packed structure. Its metallic radius is 125pm. calculate the
edge length of unit cell.
20. if NaCl is doped with
10-2 mol percentage of strontium chloride, what is the concentration of cation
vacancy?
21. KF crystallizes in fcc
structure like sodium chloride. calculate the distance between K+ and F− in KF.( given : density
of KF is 2.48 g cm−3 )
22. An atom crystallizes in
fcc crystal lattice and has a density of 10 gcm−3 with unit cell edge
length of 100pm. calculate the number of atoms present in 1 g of crystal.
23. Atoms X and Y form bcc
crystalline structure. Atom X is present at the corners of the cube and Y is at
the centre of the cube. What is the formula of the compound?
24. Sodium metal
crystallizes in bcc structure with the edge length of the unit cell 4.3 ×10−8 cm . calculate
the radius of sodium atom.
25.
Write a note on Frenkel defect.
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