1. Coordination # = 8
2 Particles per Unit Cell
Body-Centered Cubic
Sodium

2. Conduction band
3s band
Valence band
Application of a voltage to the metal (perhaps in the form of a wire) would excite electrons into the conduction band (unoccupied molecular orbitals) where they would be free to move throughout the crystal.

3. Coordination # = 12
4 Particles per Unit Cell
Face-Centered Cubic
Copper

4. ABC…ABC…ABC Stacking

5. A C B X X X X X A

6. Coordination # = 12
4 Particles per Unit Cell
Face-Centered Cubic
AKA… cubic closest packing
Copper

7. Hexagonal Unit Cell AB…AB…AB stacking Magnesium AKA…hcp
Conduction band
Valence band
Hexagonal Unit Cell
AB…AB…AB stacking
Magnesium
AKA…hcp

8. Insulator Semiconductor ex: Si or Ge
A material that doesn’t conduct electricity because the band gap is too large.
A material (whose band gap is not too big) that has low conductivity at room temp., but increases in conductivity as the temperature increases.**
**Opposite of metals whose conductivity goes down as the temperature increases.**
Insulator
Semiconductor
ex: Si or Ge

9. silicon doped with phosphorous
n-type semiconductor

10. silicon doped with boron
p-type semiconductor

11. Current flows Current does not flow
Rectifier – allows current to flow in just one direction
Current does not flow

12. Alloy: a mixture of elements that has metallic properties.
Brass
Substitutional Alloy

13. Alloy: a mixture of elements that has metallic properties.
Steel
Interstitial Alloy