Outcome 1- Intramolecular bonding: Metallic Bonding Flashcards
What is Metallic Bonding?
When positive cations bond with a sea of delocalised electrons moving through the cations
What are the physical properties associated with metallic compounds?
Good conductors of heat and electricity due to their free moving delocalised electrons, Are malleble (They can be bent or hammerd), Ductile (They can be drawn out into wires), High melting points and are often hard.
How are metals mined/ Manufactured
Very reactive metals such as K, NA and Al are extracted via electrolysis. This is when electricity is used to cause a specific chemical reaction
Mining for natural metals can only be for copper, zinc and gold as they do not tarnish or react
Are there any economical/enviromental considerations with how the metals are mined/ Manufactured
- The destruction of the landscape for open- cut mining
- Significant waste that must be disposed of
- The waste Co2 Contributes to green house effect
Alloying
A procedure that mixes a metal with other metals or non metal via melting. Alloying can change the properties of the metals or non metals.
- Atoms that are about the same size can replace each other (Substitution alloy) -Silver+ Copper= Sterling silver
- Smaller atoms may fit in the spaces in a larger atom (Interstitual alloy) - Iron+copper= Steel
Quenching
Making the metal harder but more brittle. the process of Quenching is to Heating the metal and then cooling it quickly. This makes the grain boundaries more apparent making it more brittle.
Tempering
Reduces the brittleness of the metal while retaining the hardness. The process of Tempering is to heat a quenched metal and then cool it slowly. This makes the smaller grains attach back up together making larger grains (less dislocations)
Annealing
Annealing is used to restore ductillity lost due to work hardening. work hardening =(Breaking large grains)
