Alkali Metals in Water
Lithium, sodium and potassium are all alkali metals. They sit in the first column of the periodic table, one above the other. They all react with water, but not in the same way.
Mix each metal with water in the ChemistFella lab. Watch closely and listen to Fizzy. Fill in the table for each metal, then answer the questions. Can you spot a pattern as you go down the column?
Name: Date:
What did you see?
| In water | Lithium (Li) | Sodium (Na) | Potassium (K) |
|---|---|---|---|
| Does it float? | |||
| Does it melt into a ball? | |||
| Does it catch fire? What colour? | |||
| How fast is the reaction? |
Questions
Which metal reacted most violently?
What gas makes the bubbles in all three reactions?
What has the water turned into by the end?
Rubidium is below potassium. Predict how it would react with water.
Notes for parents and teachers
This is a classic demonstration in secondary school science, but it is far too dangerous for children to do with real metals. The virtual lab lets them see the pattern safely: going down the group, each metal reacts more violently than the one above. Lithium fizzes steadily, sodium melts into a ball and zooms around, and potassium bursts into a lilac flame.
The reason is that each atom has one outer electron, and in bigger atoms it is further from the centre and easier to give away. Older children can use the last question to predict how rubidium and caesium would behave. The reaction pages for each pair have longer explanations and quizzes if children finish early.