The reactivity series
Emmanuel Opoku
Teacher
What Is the Reactivity Series?
The reactivity series is a list of metals arranged in order of how reactive they are - in other words, easily they lose electrons to form positive ions.
| Potassium |
| Sodium |
| Lithium |
| Calcium |
| Magnesium |
| Aluminium |
| Carbon |
| Zinc |
| Iron |
| Hydrogen |
| Copper |
| Silver |
| Gold |
Table 1: A list of common metals (and two non-metals) by reactivity.
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The more easily a metal loses electrons, the more reactive it is and the higher up the reactivity series it will be.
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The reactivity series is developed by observing the reactions of metals with substances like water, oxygen, and acids to rank them by reactivity.
Why Metals React?
When metals react:
They lose electrons and form positive ions (cations) in order to gain a full outer shell.
The easier it is to lose electrons, the more vigorous the reaction.
Example:
Potassium reacts violently with water because it easily loses its outer electron.
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Metals and Oxygen
When metals react with oxygen, they form metal oxides.
These reactions are oxidation reactions because the metal gains oxygen.
General equation:
Metal Oxygen Metal Oxide
Examples:
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Reactivity trend:
Highly reactive metals (e.g. magnesium) burn brightly in oxygen to form magnesium oxide.
Less reactive metals (e.g. iron, copper) slowly corrode or rust (specific to iron).
Metals and Water
Metals can also react with water to form a metal hydroxide and hydrogen gas.
This reaction becomes less vigorous down the reactivity series.
General equation:
Metal Water Metal Hydroxide Hydrogen
Examples:
Potassium: reacts explosively, lilac flame
Sodium: vigorous fizzing
Calcium: slower reaction, gentle bubbling
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Hydrogen test: when a lit splint is placed near the gas a squeaky pop sound is produced.
Metals below hydrogen (like copper, silver, gold) do not react with water.
Metals and Acids
Metals that are above hydrogen in the reactivity series will react with acids, producing a salt and hydrogen gas.
General equation:
Metal Acid Salt Hydrogen
Examples:
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Trend:
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More reactive metals faster reaction, more bubbles.
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Metals below hydrogen no reaction.
Remembering the Reactivity Series
Here’s a fun, memorable mnemonic that flows well and sticks easily:
“Please Stop Calling Me A Cute Zebra In The Library Having Coffee.”
TRY TO COME UP WITH YOUR OWN!
| Letter | Element |
| P | Potassium |
| S | Sodium |
| C | Calcium |
| M | Magnesium |
| A | Aluminium |
| C | Carbon |
| Z | Zinc |
| I | Iron |
| T | Tin |
| L | Lead |
| H | Hydrogen |
| C | Copper |
Tip: The “Library Having Coffee” ending reminds students that Hydrogen and Copper appear at the bottom — the quiet ones that don’t react much!
Silver and Gold are not included here as they are easy to remember – these are metals found naturally in their pure form – native metals - as they are not very reactive.
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Why Hydrogen and Carbon Are Included
Hydrogen and carbon are non-metals, but they’re included because:
Hydrogen helps predict whether a metal reacts with acids.
Carbon helps determine how a metal is extracted from its ore (metals below carbon can be extracted by reduction with carbon).
Check Your Understanding
Recall
a) What does the reactivity series show?
Answer
a) It shows how easily metals lose electrons (their tendency to form positive ions).
b) What gas is produced when metals react with acids?
Answer
b) Hydrogen gas.
c) Which metal reacts most vigorously with water?
Answer
c) Potassium.
Apply
d) Explain why gold and platinum are found as native metals (uncombined in the Earth).
Answer
d) They are very unreactive and lie at the bottom of the reactivity series, so they do not easily form compounds with other elements.
e) Why are these metals used for jewellery and electronics rather than for structural materials?
Answer
e) They resist corrosion and oxidation, making them ideal for decorative and high-end uses.
Challenge
f) Explain, in terms of electrons, why potassium is more reactive than sodium.
Answer
f) Potassium has more shells than sodium. The greater distance between the nucleus and the outer shell means it loses its outer electron more easily than sodium, forming ions faster and reacting more vigorously.