AQA GCSE Chemistry - Topic 4: Chemical changes - Reactivity of metals

Sep 5, 2026

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Reactivity of metals explains how metals form positive ions when they react, and how this links to their placement in the reactivity series. Notes cover oxidation and reduction using oxygen transfer, including how metal oxides form from metals reacting with oxygen. The document also shows how a more reactive metal can displace a less reactive metal from compounds. Finally, it links extraction processes to reduction and uses electron-based ideas (OIL RIG) to interpret ionic equations and decide which species is oxidised or reduced.

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Topic 4: Chemical changes

Reactivity of metals

Metal oxides and oxidation/reduction

The reactivity series

Displacement reactions

Extraction of metals and reduction

Oxidation and reduction in terms of electrons

Writing and interpreting ionic equations

AQA GCSE Chemistry Topic 4: Chemical changes Reactivity of metals Notes (Content in bold is for Higher Tier only) Metal oxides ● Metals + oxygen-> metal oxides ● Known as oxidation reactions because the metals gain oxygen ● Reduction= loss of oxygen & oxidation= gain of oxygen The reactivity series ● When metals react with other substances, metal atoms form positive ions ● Reactivity of a metal is related to its tendency to form positive ions ● Metals can be arranged in order of their reactivity in a reactivity series o Metals potassium, sodium, lithium, calcium, magnesium, zinc, iron and copper can be put in order of their reactivity from their reactions with water and dilute acids: | element | reaction with water | | --- | --- | | potassium | violent | | sodium | very quick | | lithium | quick | | calcium | more slow | | element | reaction with dilute acid | | --- | --- | | calcium | very quick | | magnesium | quick | | zinc | fairly slow | | iron | more slow | | copper | very slow | o Non-metals hydrogen and carbon are often included in the reactivity series ● A more reactive metal can displace a less reactive metals from a compound (think about how this is similar as well to halogens) Extraction of metals and reduction ● Gold, since it is very unreactive, it is found in the Earth as the metal itself ● But, most metals are found as compounds that require chemical reactions to extract the metal ● Metals less reactive than carbon can be extracted from their oxides by reduction with carbon o Don’t forget: reduction involves the loss of oxygen Oxidation and reduction in terms of electrons ● Try and remember this phrase: OIL RIG, it stands for Oxidation IsLoss and Reduction Is Gain (of electrons) ● to write ionic equations: o if sodium is oxidised, it has lost an electron, leaving it with a +1 charge, so the ionic equation is: Na-> Na+ + e o if sodium +1 ion is reduced, it has gained an electron, leaving it with a charge of zero, so the ionic equation is: Na+ + e- -> Na o remember: the charges on each side of the equation should add up to the same number ● to be able to tell which element has been oxidised and which has been reduced in an equation: o e.g. 2Na + 2HCl-> 2NaCl + H2 o HCl is made up of H+ and Cl- ions & NaCl is made up of Na+ and Cl- ions o looking at just sodium: 2Na-> 2Na+, so the ionic equation must be: 2Na-> 2Na+ + 2e-, meaning sodium has lost electrons & has been oxidised o looking at just chlorine: 2Cl- -> 2Cl-, meaning chlorine has not been oxidised or reduced o looking at just hydrogen: 2H+ -> H2, so the ionic equation must be: 2H+ + 2e- -> H2, meaning hydrogen has gained electrons so has been reduced

FAQs

What does it mean when a metal reacts and forms positive ions?

When metals react with other substances, metal atoms form positive ions. A metal’s reactivity depends on its tendency to form these positive ions, which is why metals can be ordered in a reactivity series.

How do oxidation and reduction relate to oxygen in metal oxide reactions?

Oxidation is the gain of oxygen by a substance, while reduction is the loss of oxygen. This matches the idea that metals + oxygen form metal oxides, and reduction involves losing oxygen.

How can you tell in an equation which element is oxidised or reduced?

Using the electron idea (OIL RIG), identify which species loses electrons (oxidised) and which gains electrons (reduced). In the sodium example, Na loses electrons to form Na+ (oxidised); hydrogen gains electrons to form H2 (reduced).

Sep 5, 2026

Upload by Ophelia