a) Describe the term electron cloud. What is the role of electron cloud in the Metallic bond?
b) Compare and contrast Metallic, covalent and Ionic bonds and also give exs.
a) How is metallic bond similar to both ionic and covalent bond?
b) Ionic solids are bad conductors of electricity however an aqueous or fused solution of them conducts electricity. Why?
a) Describe why carbon atoms in diamond bind covalently; while lead atoms bond metallically even via carbon and lead have four valence electrons each.
b) Distinguish between a single crystal and polycrystalline material?
a) Describe the crystallization of Metals.
b) Describe about the effect of grain boundaries on the properties of Metals or Alloys.
c) What do you mean by grain size? What is a fine grained and coarse grained material?
a) Define the terms grain and grain boundary? How does the presence of grain boundary influence the physical and mechanical properties of metals?
b) What is the effect of heating rate and cooling rate of steel on grain growth and properties of steel?
problem 6: prepare short notes on:
a) Space lattice and unit cell.
b) Co-ordination number and atomic packing factor.