Transition Metals, Alloys & CorrosionEdexcel GCSE Chemistry: Flashcards

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Name four typical properties of transition metals.

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Name four typical properties of transition metals.: High melting point, high density, form coloured compounds, catalytic activity.
What is corrosion?: The oxidation of a metal by its environment, usually reacting with oxygen and/or water, damaging the metal.
What two substances must both be present for iron to rust?: Oxygen and water — both are needed together.
Name the three ways of preventing rusting.: Exclusion of oxygen, exclusion of water, and sacrificial protection.
Explain how sacrificial protection prevents rusting.: A more reactive metal (e.g. zinc) is attached to the iron; it loses electrons more easily than iron, so it is oxidised instead of the iron.
What is electroplating used for?: To improve the appearance and/or the resistance to corrosion of a metal object, using electrolysis to coat it in another metal.
Define an alloy.: A mixture of a metal with one or more other elements, usually other metals or carbon.
Why are alloys usually stronger than pure metals?: Different-sized atoms in the alloy distort the regular layers of metal atoms, making it harder for the layers to slide over each other.
Why is iron alloyed to make steels rather than used pure?: Pure iron is too soft; alloying with carbon and other metals produces alloy steels that are much stronger and harder.
What is magnalium and what property makes it useful?: An alloy of aluminium and magnesium; it has low density and is stronger than pure aluminium, useful for aircraft/car parts.
What is brass and what is it used for?: An alloy of copper and zinc; harder than copper and resists corrosion, used for door fittings and musical instruments.
Why is copper used for electrical wiring?: Copper is a good electrical conductor and is malleable, so it can be drawn into wires.
Give an example of a coloured transition metal compound.: Iron(II) compounds are pale green; iron(III) compounds are orange-brown (also: copper compounds are typically blue).