1. Review:
For each substance, identify the type of solid, the type of attractive force holding the solid together, and make any comparisons about their relative melting points and electrical conductivity that can be made.
I2 HCl SiC NaCl NaBr

2. Chemistry of Solids

3. Goals for today:
Draw simple representations of different types of solids that illustrate important aspects of their structure
Analyze models of different solid types in order to explain the properties of these substances.

4. Metal atoms lose their valence electrons, creating positive ions
Metallic Solids:
“Sea of electrons” theory
The electrons are “delocalized” can flow freely between the ions

5. Metallic Solids:
Metal ions attracted to each other via metallic bonds.
The + ions are held in place by their attraction to the electrons surrounding them

6. Metallic Solids:
Metal ions attracted to each other via metallic bonds.
This attraction is usually comparable in strength to ionic or covalent bonds

7. Metallic Bonding

8. Metallic Solids:
Predictable Properties
Melting Point: (on your own)
Generally higher, but can vary widely
Mercury and gallium
Electrical conduction: (on your own)
Excellent conductors of electricity

9. Metallic Solids:
Not-so Predictable Properties
Thermal conduction:
Good thermal conductors
The delocalized electrons help to transfer kinetic energy throughout the metal quickly

10. Metallic Solids:
Not-so Predictable Properties + - + - +
Hardness: - + - + - + - + - + - + - + - + - + - +

11. Metallic Solids:
Not-so Predictable Properties - + - +
Hardness: + + - + - - - + - + + + - + - - - + - + +

12. Metallic Solids:
Not-so Predictable Properties - + - +
Hardness: + - + - - + - + + - + - - + - +

13. Metallic Solids:
Not-so Predictable Properties
Hardness:
(on your own)

14. Metallic Solids:
Not-so Predictable Properties
Hardness:
(on your own)

15. Metallic Solids:
Not-so Predictable Properties
Hardness:
(on your own)

16. Metallic Solids:
Not-so Predictable Properties
Hardness:
(on your own)
The rows easily re-align, but without being repelled and breaking off

17. Metallic Solids:
Not-so Predictable Properties
Hardness:
This is called malleability

18. Metallic Solids:
Not-so Predictable Properties
Easily alloyed:
An alloy is a mixture of different metals
2 Types: Interstitial and Subsitution

19. Metallic Solids:
Not-so Predictable Properties
Interstitial Alloys:
Smaller atoms wedge into the spaces between the metals

20. Metallic Solids:
Not-so Predictable Properties
Interstitial Alloys:
The interstitial atoms get in the way and make it harder to displace the rows

21. Metallic Solids:
Not-so Predictable Properties
Interstitial Alloys:
Interstitial alloys increase the hardness of the base metal

22. Metallic Solids:
Not-so Predictable Properties
Substitution Alloys:
Atoms of similar size replace the original metal atoms

23. Metallic Solids:
Not-so Predictable Properties
Substitution Alloys:
The properties of the alloy are a blend of the 2 separate metals