Transition Metals, Alloys and Corrosion Flashcards
State 3 general physical properties of transition metals
- Malleable
- Shiny
- Strong
State 3 general chemical properties of transition metals
- High melting points
- High densities
- Electrical conductors
Describe the corrosion of metals as the result of oxidation
When metals react with oxygen they lose electrons and are oxidised
Describe how rusting of iron occurs
Rusting only happens when the iron is in contact with both oxygen (from the air) and water
Explain how sacrificial protection works
A more reactive metal is placed with the metal you’re protecting so the water and oxygen react with the sacrificial metal instead
How can rusting be prevented by excluding oxygen and water
If there isn’t any oxygen then the iron can’t be oxidised to form FeO (rust)
What is electroplating
Electroplating is coating the surface of a metal with another metal using electrolysis
What are some common examples of electroplating
- Cutlery and cooking utensils are electroplated to prevent corrosion
- jewellery and decorative items are electroplated to look shiny and attractive
How is electroplating carried out
Ions from the electrolyte move towards the cathode where metal is deposited
Name a common alloy
-Bronze
How are alloys made
Alloys are made by adding another element to a metal
Why is iron alloyed with other metals
Iron on its own will rust (corrode) fairly quickly, but steel is much less likely to rust
Why are alloys stronger than the metals they contain
Different elements have different sized atoms. When a smaller element is added it makes it more difficult for the layers of pure metal to slide over each other
What is magnalium (aluminium + magnesium) used for and why
It’s used to make parts for cars and aeroplanes. This is because it is lighter and corrodes less easily
When it contains (50%) magnesium it’s used in fireworks since it burns bright but is more stable
