Water test
Reactivity of metals with water.
Violent or calm
Potassium, magnesium, iron and gold are each put in water. A teacher keeps a safe distance.
Do they all react with water in the same way?
What this lesson covers
The idea
Potassium and sodium react violently with cold water, calcium less violently, magnesium only with hot water, and aluminium, iron and zinc only with steam, while lead, copper, silver and gold never react with water.
Violent or calm
Potassium, magnesium, iron and gold are each put in water. A teacher keeps a safe distance.
Do they all react with water in the same way?
- No, the reactions differ a lot
- Yes, all are violent
- Yes, none reacts
Sort by water
Tap the group each metal belongs to.
A ladder of reactivity
Potassium and sodium react so violently and give out so much heat that the hydrogen catches fire. Calcium is less violent. Magnesium needs hot water. Aluminium, iron and zinc need steam. Lead, copper, silver and gold do not react with water at all.
Potassium and sodium react violently with cold water, calcium less violently, magnesium only with hot water, and aluminium, iron and zinc only with steam, while lead, copper, silver and gold never react with water.
- Metal | Reaction with water
- K, Na | violent, with cold water
- Ca | less violent, with cold water
- Mg | hot water only
- Al, Fe, Zn | steam only
- Pb, Cu, Ag, Au | no reaction
Notes
K, Na: violent with cold water; Ca: less violent; Mg: hot water; Al, Fe, Zn: steam; Pb, Cu, Ag, Au: no reaction.
Check yourself
Which of these reacts violently with cold water?
Which metal reacts with hot water but not with cold water?
Iron reacts with ...
Which of these does not react with water at all?
- Magnesium. Magnesium does not react with cold water; it reacts with hot water.
- Aluminium. Aluminium reacts only with steam, not with cold water.
- Sodium — correct. Yes!
- Magnesium — correct. Yes!
- Potassium. Potassium reacts violently even with cold water.
- Lead. Lead does not react with water at all.
- cold water. Iron does not react with cold or hot water.
- steam — correct. Yes!
- no form of water. Iron does react with steam to form the metal oxide and hydrogen.
- Aluminium. Aluminium does react, with steam.
- Zinc. Zinc does react, with steam.
- Copper — correct. Yes!