This question is about the elements in Group 1 of the Periodic Table (the alkali metals).
Lithium, sodium, and potassium all react in a similar way. Explain why in terms of their electronic structure.
A student investigates the reaction of these three elements with water.
The table shows some of the student's observations and reaction times:
| Group 1 element | Time for element to react completely (s) | Observations |
|---|---|---|
| Lithium | 35 | Fizzes, floats and moves slowly on the surface of the water. |
| Sodium | 18 | Fizzes vigorously, melts into a silvery sphere, moves quickly on the surface. |
| Potassium | 8 | Fizzes extremely violently, melts into a sphere, ignites with a lilac flame, moves very quickly on the surface. |
All three elements produce the same gas when they react with water. Name this gas.
Describe how you would test for this gas and state the positive result.
Caesium (Cs\text{Cs}Cs) is another Group 1 element. It is located below rubidium (Rb\text{Rb}Rb) in the periodic table.
Predict the observations and the reaction time when a similar sample of caesium reacts with water. Include a word or balanced symbol equation for this reaction.