Chemical changes involve reactions where metals interact with oxygen, acids,...
Chemistry224 views·Updated 23 Aug 2026·3 pagesUnderstanding Chemical Changes AQA Notes
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Reactivity of Metals
Ever wondered why some metals rust faster than others or why gold stays shiny for centuries? It's all about reactivity - how eagerly a metal wants to lose electrons and form positive ions.
The reactivity series ranks metals from most to least reactive. Metals like potassium, sodium, and calcium sit at the top because they lose electrons really easily. Gold and platinum hang out at the bottom, barely reacting with anything.
When metals meet acids, they follow a simple pattern: ACID + METAL → SALT + HYDROGEN. You can actually see how reactive a metal is by watching how fast the hydrogen bubbles form. Potassium reacts explosively (don't try this at home!), whilst copper barely bothers to react with cold, dilute acids.
Metal extraction depends entirely on where a metal sits in this series. If it's below carbon (like zinc or iron), we can use carbon to extract it cheaply. Metals above carbon need expensive electrolysis to extract them - that's why aluminium used to be more valuable than gold!
Quick Tip: Remember OIL RIG - Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons). This helps you identify what's happening in metal reactions.
2
of 3
Redox and Displacement Reactions
Redox reactions are everywhere in chemistry - they're simply reactions where electrons move from one substance to another. The name comes from REDuction and OXidation happening simultaneously.
Displacement reactions are brilliant examples of redox in action. A more reactive metal literally kicks a less reactive metal out of its compound. Think of it like queue-jumping - the more aggressive metal takes the place of the weaker one.
Here's what happens: when you drop iron into copper sulphate solution, the iron loses electrons (gets oxidised) whilst the copper ions gain those electrons (get reduced). You'll see the blue solution turn colourless as shiny copper metal appears.
Ionic equations make these reactions clearer by showing only the particles that actually change. The spectator ions (like chloride ions that don't react) get ignored - they're just watching from the sidelines.
Real-World Connection: Displacement reactions happen in galvanising (coating iron with zinc) and in extracting metals from ores. Understanding this helps explain why some metals are better for certain jobs.
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of 3
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Chemistry224 views·Updated 23 Aug 2026·3 pagesUnderstanding Chemical Changes AQA Notes
A
AK Squad@aksquad_hoka
Chemical changes involve reactions where metals interact with oxygen, acids, and water in predictable ways. Understanding how metals behave in these reactions helps us extract useful materials and predict what happens when different substances meet.
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Reactivity of Metals
Ever wondered why some metals rust faster than others or why gold stays shiny for centuries? It's all about reactivity - how eagerly a metal wants to lose electrons and form positive ions.
The reactivity series ranks metals from most to least reactive. Metals like potassium, sodium, and calcium sit at the top because they lose electrons really easily. Gold and platinum hang out at the bottom, barely reacting with anything.
When metals meet acids, they follow a simple pattern: ACID + METAL → SALT + HYDROGEN. You can actually see how reactive a metal is by watching how fast the hydrogen bubbles form. Potassium reacts explosively (don't try this at home!), whilst copper barely bothers to react with cold, dilute acids.
Metal extraction depends entirely on where a metal sits in this series. If it's below carbon (like zinc or iron), we can use carbon to extract it cheaply. Metals above carbon need expensive electrolysis to extract them - that's why aluminium used to be more valuable than gold!
Quick Tip: Remember OIL RIG - Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons). This helps you identify what's happening in metal reactions.
2
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Redox and Displacement Reactions
Redox reactions are everywhere in chemistry - they're simply reactions where electrons move from one substance to another. The name comes from REDuction and OXidation happening simultaneously.
Displacement reactions are brilliant examples of redox in action. A more reactive metal literally kicks a less reactive metal out of its compound. Think of it like queue-jumping - the more aggressive metal takes the place of the weaker one.
Here's what happens: when you drop iron into copper sulphate solution, the iron loses electrons (gets oxidised) whilst the copper ions gain those electrons (get reduced). You'll see the blue solution turn colourless as shiny copper metal appears.
Ionic equations make these reactions clearer by showing only the particles that actually change. The spectator ions (like chloride ions that don't react) get ignored - they're just watching from the sidelines.
Real-World Connection: Displacement reactions happen in galvanising (coating iron with zinc) and in extracting metals from ores. Understanding this helps explain why some metals are better for certain jobs.
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We thought you’d never ask...
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
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Students love us — and so will you.
4.6/5App Store
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan SiOS user
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