Describe the unit cell of lithium (see Figure).

Using circles, draw regular two-dimensional arrangements that demonstrate low packing efficiency and high packing efficiency.

8.76 Using circles, draw regular two-dimensional arrangements that demonstrate low packing efficiency and high packing efficieny.

Silicon carbide, SiC, is a very hard, high-melting solid. What kind of crystal forces account for these properties?

a) Solid materials may exist in the crystalline form, either as a single crystal or a polycrystalline. Define the term crystalline material.

Define the terms viscosity, capillary action and surface tension. a. How do the viscosity and surface tension of liquids change as intermolecular forces become stronger? Explain. b. How do the viscosity and surface tension of liquids change as temperature increases? Explain

VIII. Comparison between an amorphous and crystalline solid. Physical Properties Amorphous Crystalline texture melting point compressibility breakability

4. List types of crystal imperfections, give their dimensionality and examples.

1. Does the diagram best describe a crystalline solid, a liquid, or a gas? Explain.  2. In terms of the arrangement and freedom of motion of the molecules, how are the nematicliquid crystalline phase and an ordinary liquid phase similar? How are they different? 3. It often happens that a substance possessing a smectic liquid crystalline phase just abovethe melting point passes into a nematic liquid crystalline phase at a higher temperature.Account for the type of behavior.