1. Metallic Bonding
Noadswood Science, 2012

2. Metallic Bonding
Wednesday, April 26, 2017
To understand how the structure of metals affect their properties

3. Summary Quiz
For each of the following say if it is ionic, simple covalent or giant covalent
Are you able to identify what it is?

4. Question 1 Diatomic green gas Melting point -101°C
Boiling point -34.6°C
Answer – chlorine (simple covalent)

5. Question 2 Very hard Tetrahedral structure Boiling point 2230°C
Used in desiccants (substance which induces dryness)
Answer – silicon dioxide (giant covalent)

6. Question 3 Blue crystals Will dissolve
Conducts electricity when molten
Answer – copper sulfate (ionic)

7. Question 4 Pungent smelling gas Can be used in explosives
Answer – ammonia (simple covalent)

8. Question 5 Dangerous substance Contains carbon
Made by incomplete combustion
Answer – carbon monoxide (simple covalent)

9. Question 6 Solid at room temperature
When made gives out a lot of light
White powder
Answer – magnesium oxide (ionic)

10. Metals Where are metals found on the periodic table?
Metal are found at the left and centre of the periodic table…

11. Metallic Bonding
Metals form giant structures in which electrons in the outer shells of the metal atoms are free to move
The metallic bond is the force of attraction between these free electrons and metal ions – metallic bonds are strong, so metals can maintain a regular structure and usually have high melting and boiling points

12. Properties
Metal ions form a lattice which is more tightly packed and denser than the lattices in ionic compounds – they form crystals called grains
Metals are good conductors of electricity and heat, because the free electrons carry a charge or heat energy through the metal
The free electrons allow metal atoms to slide over each other, so metals are malleable and ductile
Metals generally have a very high melting and boiling point because metallic bonds are very strong and so a large amount of energy is needed to break them

13. Properties – Conductivity
Metals are good conductors of heat – the free electrons can take in heat energy, which makes them move faster and they can then transfer the energy throughout the lattice
Metals are good conductors of electricity – the free electrons can carry an electrical charge (silver is the best conductor, but is very expensive)!

14. Properties – Strength
Metals are usually tough, not brittle – when a metal is hit, the layers of the lattice just slide over each other
The metallic bonds do not break because the electrons are free to move
This means metals are malleable (bent and pressed) and ductile (be drawn out into wires)

15. Properties – Grains
Layers of atoms can slip over each other in metal grains when a force is applied, but this slippage stops at grain boundaries
The smaller the grains, the shorter the distance the atom layers can move meaning metals with smaller grains are stronger and harder than metals with larger grains
The faster that molten metal is cooled, the smaller the grain size

16. Anagrams

17. Quiz