The table shows data about the alkali metals.
| Alkali metal | Melting point / °C | Density / g cm−3\mathrm{g\,cm^{-3}}gcm−3 |
|---|---|---|
| lithium | 181 | 0.53 |
| sodium | 98 | 0.97 |
| potassium | 63 | 0.86 |
| rubidium | 39 | 1.53 |
| caesium | 28 | 1.93 |
A student makes this claim: "Down group 1, the melting point decreases and the density increases." Evaluate the student's claim using the data.
Francium is below caesium in group 1. Predict the density of francium.
Water has a density of 1.00 g cm−3\mathrm{g\,cm^{-3}}gcm−3. Give the names of the alkali metals in the table that would float on water.
When sodium reacts with water it melts into a ball, but lithium does not melt when it reacts with water. Explain this difference. Use the data in the table and your knowledge of the reactions in your answer.
The alkali metals are named because of the solutions they form with water. Explain why.
41 exam-style questions on Edexcel GCSE Chemistry 7.1 Group 1, covering 7.1.1 Classifying elements by group in the periodic table and 7.1.2 Properties and reactions of the alkali metals. Each one has a worked solution and a mark scheme showing where the marks go.