1. Properties of Solids

2. Intermolecular Forces of Attraction
Ch. 11 is about liquids and solids… where the attraction between particles allows the formation of solids and liquids.

3. Four Solids – Overview
•Molecular Solids (particles with IMF’s) •Covalent Network Solids (covalent bonding) •Ionic Solids (ionic bonding) •Metals (metallic bonding)

4. Molecular Solids Strong covalent forces within molecules
Weak covalent forces between molecules
Properties:
Relatively soft
Low melting points (<200°C)
Poor conductors of heat or electricity

5. Molecular Solid Examples
H2O - ice Dry Ice - CO2

6. Molecular Solid Examples
Sugar crystals
Extensive hydrogen bonding in ice holds the water molecules farther apart in a more ordered arrangement than in liquid water. The hexagonal symmetry of a snowflake reflects the structure of the ice crystal.

7. Covalent Network Solids
Some covalent substances do not form discrete molecules
Atoms are covalently bonded in large networks or chains by covalent bonds.
Properties:
Very hard
Very high melting points

8. Covalent Network Solid Examples
Diamond, C(s)
All carbons connected by covalent bonds
One of the strongest materials.

9. Covalent Network Solid Examples
Graphite, C(s)
Sheets of covalent networks of carbon weakly bonded to another sheet
(used in pencils)

10. Covalent Network Solid Examples
SiO2 (quartz, sand, glass)

11. Covalent Network Solid Examples
Si (s)

12. Ionic Solids Attraction of positive and negative ions.
Form crystalline structures.
Properties:
Hard and brittle
High melting point
Poor conductor of heat and electricity

13. Ionic Solids
•A lattice of positive and negative ions

14. Metallic Solids
Valence electrons are delocalized (freely floating) throughout the entire solid. “Sea of electrons”
Form crystalline structures
Properties:
Excellent conductors of heat and electricity
Malleable and ductile
Varying hardness and melting points

15. Metals

16. Metal Examples

17. Summary – Strength of Inter- and Intramolecular Forces
•London Dispersion Force
Dipole-Dipole Interactions
Hydrogen Bonds
Ion-Dipole Interactions
Ionic Bonds (Ion-Ion)
Covalent Bonds
Covalent Network