A laboratory technician is preparing a video demonstration comparing the reactions of three Group 1 metals: sodium, potassium, and rubidium with water.
They compile a reference table of physical properties and expected behaviors:
| Metal | Density (g cm−3\text{g cm}^{-3}g cm−3) | Melting point (∘C^\circ\text{C}∘C) | Behavior on/in water | Other observations |
|---|---|---|---|---|
| Sodium | 0.97 | 98 | Floats and melts into a silver sphere | Fizzes rapidly, moves quickly, dissolves |
| Potassium | 0.86 | 63 | Floats and melts instantly | Fizzes violently, ignites spontaneously with a lilac flame |
| Rubidium | 1.53 | 39 | Sinks rapidly | Reacts explosively, shattering the vessel if not carefully controlled |
Describe, in detail, the essential safety protocols the technician must implement to perform this demonstration safely, and explain how the physical properties (density and melting point) and chemical observations in the table show the trend in reactivity and behavior down Group 1.
Practise Edexcel GCSE Chemistry Group 1 with exam-style questions for Foundation and Higher tier. 51 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
