Who Reacts Hardest?
Rank metals by how vigorously they react.
What this lesson covers
Why it matters
Drop a tiny piece of potassium into water and it whizzes across the surface in a lilac flame. Try the same with copper and… nothing. Metals are not all equally eager to react.
Predict first
Which of these metals reacts most vigorously?
Potassium is the most reactive here — it reacts violently even with cold water. The order from most to least reactive is potassium, sodium, zinc, then copper.
- Copper
- Potassium — correct
- Zinc
- They all react exactly the same
What you do
Drag these metals into order of reactivity, from the most reactive at the top to the least reactive at the bottom.
Check yourself
Which metals are reactive enough to react even with cold water?
Only the most reactive metals, such as potassium and sodium, react with cold water. Less reactive metals need steam or do not react with water at all.
Which statement about unreactive metals is correct?
Copper and gold sit low in the reactivity series, so they react only weakly or not at all. That is why gold jewellery does not tarnish or corrode easily.
Why are gold and platinum found free (uncombined) in nature?
Gold and platinum are at the very bottom of the reactivity series. Being so unreactive, they do not readily form compounds, so they are found as the free metal in nature.
- Very reactive metals like potassium and sodium — correct
- Unreactive metals like copper and gold
- All metals react with cold water
- No metal ever reacts with water
- Metals like copper and gold barely react — correct
- Metals like copper and gold react most violently of all
- Unreactive metals react strongly with cold water
- Unreactive metals catch fire in air at once
- Because they are so unreactive they do not combine with other elements — correct
- Because they are so reactive they burst out of their compounds
- Because they dissolve in water and float up
- Because they are lighter than air