True or False?
Shape memory Alloys
1. Metals are arranged in layers.
2. Alloys contain only one type of atom.
3. Metals have high boiling points
4. Shape memory alloys return to their orignial shape when heated.
5. Metallic structures doesn't contain any free electrons.
6. Metals conduct electricity.
Independent Activity
AQA Chemistry Text page 130-131
Complete the summary questions on page 131.
Extension
Complete question 3 on page 136
Complete question 5a on page 137
Examples of alloys
Giant Metallic Structures
- Steel - Carbon and Iron
- Stainless steel – Carbon, Steel and Nickel
- Brass – Copper and Zinc
- Solder – Lead and Tin
- White gold – Gold, Nickel and Palladium
What is an Alloy?
- An alloy is a mixture of metals
- In alloys the layers cannot slide so easily making them harder than pure metals.
Learning Objectives
What is metallic bonding?
- Metallic bonding is the bonds that hold metal atoms together.
- Contains a sea of electrons
D - state the physical properties of metal and what an alloy is.
C- explain why metals can be bent into different shapes.
B -Explain what a shape memory alloy is and give an example.
A- Explain why metals conduct electricity and energy in terms of delocalised electrons in their structures.
A* - Explain how delocalised electrons explain the other properites of metals.
Starter
What physical properties can metals have?
Physical properties of metals
Heat conductor
Lustrous (shiny)
High Melting/Boiling points
Hard
Electrical conductor
Dense
High tensile strength
Ductile