1. The Solid State:
Types of solids

2. Crystalline solids have a regular arrangement
Ionic Solids (NaCl)
Molecular solids (sucrose)
Atomic or elemental solids (graphite, diamond)

3. Properties of a solid are determined by the nature of the forces between their particles (intermolecular/intramolecular)

4. Ionic Solids:
oppositely charged ions are held together by strong forces of attraction
Conduct a current in solution as ions are free to move
Stable substances with high melting points (solids at room temp)

5. Ionic Solids
Larger negative ions are packed together with smaller positive ions occupying spaces between them.

6. Molecular Solids
Carbon Dioxide (CO2)
Phosphorus (P4)
Sulfur (S8)

7. Forces are much weaker than in ionic solids
London dispersion forces
may have dipole-dipole attractions
 melt at lower temperatures

8. Atomic Solids Covalent Network Solids
Properties vary greatly, depending on how the atoms interact
Noble gases
London dispersion forces
very low melting points ( Neon: º C )
Diamond (carbon)
covalent bonds between carbon atoms form a network solid
very high melting point (>3500 C)

9. Bonding in Metals Bonds are strong and nondirectional
difficult to separate atoms, but easy to slide them past each other

10. Electron sea model
valence electrons are shared and free to move around (makes metals good conductors)

11. This bonding accounts for malleability, ductility, high melting points and durability of metals.
Movement of electrons make metals good conductors

12. Alloys
substances that contain a mixture of elements and have metallic properties
There are 2 types of alloys
substitutional alloy
interstitial alloy

13. Substitutional alloys
some atoms are replaced by similarly sized atoms
Brass: 67% Cu, 33% Zn

14. Sterling silver: 93% Ag, 7% Cu

15. Interstitial alloy Inter-: between; -stitial: spaces
Smaller atoms fit in “holes” (interstices) between atoms
Steel: Iron and carbon
Carbon atoms form directional bonds, which give strength, increase hardness and decrease ductility

16. Amount of carbon affects type of steel
Mild steels (<0.2%C): nails, cables, chains

17. Medium steels (0.2-0.6%C): structural steel, rails

18. High-carbon steels (0.6-1.5%C): springs, tools, cutlery

19. Stainless steel
Chromium and nickel atoms are substituted for some iron to better resist corrosion