Understanding Metals and Their Reactions

Properties and Reactivity of Metals

Metals are a class of elements that exhibit unique properties such as high thermal and electrical conductivity, malleability, and ductility. The reactivity of metals varies, and this is described by the reactivity series.

The Reactivity Series

The reactivity series is an arrangement of metals in descending order of their reactivity with water and dilute acids. The more reactive a metal is, the more easily it loses electrons to form positive ions.

• Potassium (K), Sodium (Na), Calcium (Ca), Magnesium (Mg) - Highly reactive metals
• Aluminum (Al), Zinc (Zn), Iron (Fe), Tin (Sn) - Moderately reactive metals
• Lead (Pb), Copper (Cu), Silver (Ag), Gold (Au) - Unreactive metals

Displacement Reactions

Displacement reactions occur when a more reactive metal displaces a less reactive metal from its compound. This reaction is represented as:

Metal A + Compound of Metal B → Compound of Metal A + Metal B

Worked Example

Problem: Predict the products when iron is added to a copper sulfate solution.

Solution:

1. Iron (Fe) is more reactive than copper (Cu) in the reactivity series.
2. The reaction is: Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)
3. Products are iron(II) sulfate solution and copper metal.

Metal Extraction

Metals are extracted from their ores using various methods, depending on their reactivity.

• Electrolysis: Used for extracting unreactive metals like aluminum from molten compounds.
• Reduction with carbon: Reactive metals like iron are extracted by reduction with carbon or carbon monoxide.
• Displacement: Very reactive metals like sodium and potassium are extracted by displacement with another reactive metal.

These processes often involve oxidation and reduction reactions, where electrons are transferred between species.