Overview
This lecture covers the reactivity series of metals, their reactions with acids and water, and how the reactivity series predicts displacement reactions.
The Reactivity Series of Metals
- The reactivity series ranks metals by how easily they lose outer shell electrons to form positive ions.
- Group 1 metals are the most reactive; group 2 are less reactive, and transition metals are generally the least reactive.
- Carbon and hydrogen, though not metals, are included as reference points in the series.
Metal Reactions with Acids
- Metals react with acids to produce a salt and hydrogen gas.
- The reaction is most violent for highly reactive metals (e.g., potassium), becoming less vigorous down the series.
- Copper typically does not react with acids.
- Reactivity with acid can be measured by bubble production, disappearance of metal, or temperature change.
- Use equal mass, surface area, and acid concentration to fairly compare metal reactivity.
Metal Reactions with Water
- Reactive metals form a metal hydroxide and hydrogen when reacting with water.
- Only the most reactive metals (like lithium) react readily with water; zinc, iron, and copper do not react at all.
- Magnesium reacts very slightly with water.
Displacement Reactions
- A more reactive metal can displace a less reactive metal from a compound in solution.
- Example: Magnesium added to iron sulfate forms magnesium sulfate and iron.
- A less reactive metal (like copper) cannot displace a more reactive metal (like iron) from its compound.
Key Terms & Definitions
- Reactivity series — a list ranking metals by how easily they form positive ions.
- Displacement reaction — a reaction where a more reactive element replaces a less reactive one in a compound.
- Metal hydroxide — a compound formed when a metal reacts with water.
- Salt — a compound formed from the reaction of an acid with a metal.
Action Items / Next Steps
- Review examples of metals reacting with acids and water.
- Practice predicting products of displacement reactions using the reactivity series.