SOLID STATE
1. Nacl is an example of ionic solid.
2. If the number of closed packed spheres is 6 its tetrahedral voids is 12.
3. NH3 is an example of polar molecular crystal solids.
4. Amorphous solids is otherwise called pseudo solids.
5. FeS will exhibit metal deficiency defect.
6. Relation between diamond and graphite is polymorphous.
7. Co-ordination number of CsCl is 8:8.
8. Ionic solids conduct electricity in molten state.
9. Wavelength of x-ray is in the order of 10-8 cm.
10. Crystalline solids are true solids.
11. Transition metals with variable valency is found in metal deficiency defect.
12. Ice is a covalent molecular crystal.
13. The number of close neighbours in BCC is 8.
14. A regular 3 dimensional arrangements of individual points in space is called space lattice.
15. Covalent solids exhibit high melting point.
16. Total number of elements of symmetry in cubical crystal is 23.
17. Co-ordination number in ABAB type arrangement is 6.
18. In FCC, an atom at face contributes to ½ part of the unit cell.
19. Bragg’s equation is n λ=2 d sinθ .
20. Essential condition to use Bragg’s equation is diffraction.
21. Correct order of packing efficiency is FCC > BBC >SC .
22. Total number of atoms in FCC is 4.
23. ABAB type of packing is seen in hexagonal close packing.
24. Co-ordination number of ZnS is 4.
25. Solids have strong cohesive force.
26. Atomic orbitals comes under crystalline solids.
27. Meaning of krystallos is clear ice.
28. Anisotropy depends on the direction of measurement.
29. Silicon carbide is a covalent solids.
30. Molecular solids don’t conduct electricity.
31. Graphite is used as lubricants because it is slippery.
32. Basic repeating structural unit is called unit cell.
33. In metallic solids, positive metal ions and a cloud of electron pervades the space.
34. The number of nearest neighbours surrounding a particle in a crystal is called coordination number.
35. There are 7 primitive crystal systems.
36. Co-ordination number in SC is 6.
37. Packing efficiency in SC is 52.38%.
38. Tetrahedral voids generated is equal to 2n.
39. Ferromagnetic materials can be demagnetized by imperfections.
40. A process called doping leads to a crystal imperfection and increases electrical conductivity.
41. Stoichiometric defect is called intrinsic or thermodynamic defect.
42. Anionic vacancies are occupied by unpaired by unpaired electrons are called f centres.
