Metals and Alloys Flashcards
What is metallic bonding?
Bonding formed by the electrostatic attraction between positive metal ions and the sea of delocalised electrons.
Why are metals good conductors?
Delocalised electrons flow and carry a charge and potential to conduct.
Why are metals malleable and ductile?
They’re arranged in layers which slide over each other.
What are alloys?
A mixture of a metal with another element.
Brass is an alloy. What is it made of?
copper and zinc
Steel is an alloy. What is it made of?
Iron, chromium, nickel, carbon…
Why are alloys stronger and harder than metals?
Different sized atoms disrupt regular structure, making it difficult for the layers to slide over each other.
What is a redox reaction?
A reaction which includes both oxidation and reduction.
What is oxidation?
Gain in oxygen, loss of electrons, increased oxidation number
What is reduction?
Loss in oxygen, gain of electrons, decreased oxidation number
What is the oxidation state of a pure element?
0, neutral
What is the sum of the oxidation number in a compound?
0, neutral
What is an oxidising agent?
A substance reduced in the process of oxidising another.
What is a reducing agent?
A substance oxidised in the process of reducing another.
What is necessary for rusting?
Water and oxygen
What are some common barrier methods?
Greasing, painting, covering in plastic material
What is galvanising?
The use of zinc to protect steel/iron/a less reactive metal from rusting by its own slow sacrifice.
How does sacrificial protection work?
A more reactive metal reacts with water instead of the metal it is protecting.
How are more reactive metals extracted from their ores?
electrolysis
How are moderately reactive metals extracted from their ores?
reduction via use of coke
How is aluminium extracted from its ore?
electrolysis
What is the aluminium ore?
bauxite
