Overview
This lecture covers the reactivity series of metals, their reactions with acids and water, and how the series predicts outcomes of displacement reactions.
The Reactivity Series of Metals
- The reactivity series ranks metals by how easily they form positive ions.
- Group 1 metals are most reactive, group 2 metals are less reactive, and transition metals are generally least reactive.
- Carbon and hydrogen, though not metals, are often included in the series as reference points.
Metals Reacting with Acids
- Metals react with acids to produce a salt and hydrogen gas.
- Highly reactive metals (like potassium) react violently or explosively with acids.
- Less reactive metals (like magnesium, zinc, and iron) react with decreasing intensity.
- Copper usually does not react with acids.
- The amount of heat produced indicates the metal's reactivity.
- To compare reactivity fairly, keep metal mass, surface area, and acid concentration the same.
Metals Reacting with Water
- Reactive metals form metal hydroxides and hydrogen gas when reacting with water.
- Only the most reactive metals (e.g., lithium) react readily with water.
- Magnesium reacts only slightly with water.
- Zinc, iron, and copper do not react with water.
Displacement Reactions
- A more reactive metal can displace a less reactive metal from its compound in solution.
- Magnesium can displace iron from iron sulfate, forming magnesium sulfate and iron.
- Copper cannot displace iron from iron sulfate as it is less reactive.
Key Terms & Definitions
- Reactivity Series — An ordered list of metals based on how readily they form positive ions.
- Displacement Reaction — A reaction where a more reactive element replaces a less reactive one in a compound.
Action Items / Next Steps
- Review the order of metals in the reactivity series.
- Practice predicting the products of metal reactions with acids, water, and in displacement reactions.