Back to Chemistry
Chemistry · Periodic table · Group I
Reactivity of Group I metals with water
Pieces of lithium, sodium and potassium are dropped onto water containing phenolphthalein indicator. Each metal reacts to give a metal hydroxide and hydrogen — but reactivity increases sharply going DOWN the group.
Observations
Lithium
Drop the metal to observe.
Sodium
Drop the metal to observe.
Potassium
Drop the metal to observe.
Exam-style questions
1. What is the general equation for a Group I metal reacting with water?
2. Why does potassium burn with a lilac flame but lithium does not?
3. Phenolphthalein indicator was added to the water at the start. After the reaction, why does it turn PINK?
4. Why does reactivity INCREASE going DOWN Group I?