1. Structure and Properties of Solids
4.8

2. Structure of Solids
Crystalline: atoms, ions, or molecules are well ordered. Have a well-defined melting point. Often the solid has regular shapes.
Amorphous: no order to the particles. Examples are glass and rubber. Have no defined mp; they soften over a range of temperatures (important for glass blowing)

3. Unit cell: crystal lattice
In a brick wall there is a repeating pattern, as there is with most wallpaper
In a crystalline solid there is a repeating pattern - the unit cell. The unit cell repeats to make the crystal lattice

4. The seven unit cells

5. Three Cubic lattices

6. Close Packing

7. Another way of looking at it

9. Diamonds are a …..

10. Some ionic solids- lattice decided by size & charge

11. From sea to shining ... array of metal ions in a sea of electrons
A sea of valence electrons
Electrons not tightly held but can move
Explains electrical conduction
Also explains optical properties - most metals “shine”