2.4 Giant Metallic Structures Flashcards
What are metals useful for and why?
Making wires, rods and sheet materials because they are ductile
What are alloys?
Mixtures of metals or metals mixed with other elements
How do the other elements in alloys affect the structure?
The more atoms of different sizes there are, the more the layers are unable to slide over each other and bend, this causes them to be brittle and break more easily and they are harder than pure metals
What are shape memory alloys?
Alloys that can be bent or deformed in a different shape but remember their original shape after being heated
Name a use of shape memory alloys
Dental braces or holding broken bones in place whilst they heal
Give 2 reasons why alloys can be more useful than pure metals
- they are harder than pure metals
* they can be made to have specific properties or special properties like shape memory polymers
Describe the atomic structure of metal.
Regularly arranged positive ions in a sea of delocalised electrons
Why are metals good conductors of electricity?
They have delocalised electrons that move throughout the giant metallic lattice and transfer energy quickly
Why can layers in alloys not slide so easily over each other? What does this cause them to be?
They can’t slide easily because atoms of other elements change the regular structure, causing them to be brittle
Name the elements in the bronze alloy
Copper and tin
What is bronze used for?
Used by civilisations before iron extraction methods were developed
Name the elements in the brass alloy
Copper and zinc
What is brass used for?
Door knobs and musical instruments because they do not tarnish
Name the elements in solder alloy
Tin and lead
What is a use of solder?
Attach components to circuit boards in electronics
Name the elements in amalgam alloy
Mercury and silver or tin
What is a use of amalgam?
Can be shaped when it’s warmer and resists corrosion
Why can metals bend/why are they ductile?
When a force is applied the metal atoms can slide over each other because they are arranged in layers
Name the diagonal arrangement when shape memory alloys are cold
Monoclinic arrangement or martensite
Name the horizontal arrangement of shape memory alloys when they’re hot
Cubic arrangement or austenite
