Exothermic, endothermic and the reactivity series
Every reaction moves energy as well as atoms. Some warm their surroundings, some cool them — and knowing which metals react hardest lets you predict the result before you mix anything.
Part of your national curriculum
- Chemistry: chemical reactions: Understand exothermic and endothermic chemical reactions and the reactivity series of metals
Lesson overview
What you'll learn in this lesson
Understand exothermic and endothermic chemical reactions and the reactivity series of metals
Key learning points
- • Energy in and out
- • The reactivity series
- • Reactions as rearrangement
This lesson at a glance
- 25 minutes
- 20 parts to scroll through
- 4 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 20
Visual introductionPicture this
Exothermic, endothermic and the reactivity series
Every reaction moves energy as well as atoms. Some warm their surroundings, some cool them — and knowing which metals react hardest lets you predict the result before you mix anything.
In a nutshell
Understand exothermic and endothermic chemical reactions and the reactivity series of metals
Learning cycle
Part 2 of 20
Learning cycle 1 of 2
Part 1 · Energy in and out
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 20
Learn
Energy in and out
An exothermic reaction transfers energy to the surroundings, so the temperature rises: combustion, neutralisation and most oxidation reactions. An endothermic reaction takes energy in, so the temperature falls: thermal decomposition and some dissolving reactions such as certain sports cold packs.
Reset break
Part 4 of 20
Pause
That's sitting 1 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 20
Learn
The reactivity series
Potassium, sodium, calcium, magnesium, aluminium, zinc, iron, lead, copper, silver, gold — from most to least reactive. A more reactive metal will displace a less reactive one from its compound, and reactivity predicts how vigorously a metal reacts with water or acid.
Quick check
Part 6 of 20
Quick check
Part 7 of 20
Reset break
Part 8 of 20
Pause
That's sitting 2 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 20
Learning cycle 2 of 2
Part 2 · Reactions as rearrangement
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 20
Learn
Reactions as rearrangement
No atoms are created or destroyed. In magnesium + copper sulfate → magnesium sulfate + copper, the same atoms end up in different partnerships, which is why mass is conserved and equations balance.
Quick check
Part 11 of 20
Reset break
Part 12 of 20
Pause
That's sitting 3 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 13 of 20
Explore the idea
Part 14 of 20
Worked example
Worked example: predicting a displacement
Will zinc react with copper sulfate solution? Zinc sits above copper in the series, so yes: zinc + copper sulfate → zinc sulfate + copper. The blue colour fades and a pink-brown copper deposit forms. Reversing the pair — copper with zinc sulfate — gives no reaction, because copper is less reactive.
Challenge round
Part 15 of 20
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Reset break
Part 16 of 20
Pause
That's sitting 4 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 17 of 20
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
An ____ reaction transfers energy to the surroundings, so the temperature rises: combustion, neutralisation and most oxidation reactions.
An ____ reaction takes energy in, so the temperature falls: thermal decomposition and some dissolving reactions such as certain sports cold packs.
A more reactive metal will displace a less reactive one from its compound, and ____ predicts how vigorously a metal reacts with water or acid.
Challenge round
Part 18 of 20
Game · Recall cards
What happens to temperature during an exothermic reaction?
Card 1 of 4
Mastery quiz
Part 19 of 20
Marked quiz
End of lesson quiz: Exothermic, endothermic and the reactivity series
4 questions, marked with the reasoning shown. No timer.
1. What happens to temperature during an exothermic reaction?
2. Which of these metals is most reactive?
3. What can a more reactive metal do to a less reactive metal's compound?
4. What happens to the temperature in an exothermic reaction?
Lesson round-up
Part 20 of 20
Lesson round-up
Ready when you are
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Ask LunaPart 1 of 20 · Watch & discover
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Understand exothermic and endothermic chemical reactions and the reactivity series of metals