Topic 15 - Reactivity Series (2)

Reactivity Series

• Definition: Lists elements, primarily metals, according to decreasing reactivity.

  • Order of Reactivity: Potassium (K) > Sodium (Na) > Lithium (Li) > Calcium (Ca) > Magnesium (Mg) > Aluminium (Al) > Zinc (Zn) > Iron (Fe) > Copper (Cu) > Silver (Ag) > Gold (Au)

Importance of Carbon in the Reactivity Series

• Role: Carbon is included due to its significance in extracting metals from metal oxides.

  • Extraction Process: Heating metal oxides with carbon removes oxygen when the metal is less reactive than carbon.

  • Many metals are encountered as oxides and require purification to extract the metal.

Reactions of Metals

• Electron Loss: Metals react by losing electrons, hence undergoing oxidation.

• Types of Reactions:

  • With water/steam.

  • With halogens.

  • With acids.

  • Displacement reactions.

  • With oxygen.

• Exothermic Nature: All reactions generate heat, making the mixture warm.

Reactions with Oxygen

• Metals react with oxygen to yield metal oxides:

  • General Equation: METAL + OXYGEN → METAL OXIDE

Reactions with Water

• Formation of Hydroxides:

  • Equation: 2Na + 2H2O → 2NaOH + H2

  • General Form: METAL + WATER → METAL HYDROXIDE + HYDROGEN

• Reactivity with Steam: Metals respond with steam to generate both metal oxides and hydrogen gas.

Reactions with Acids

• Metals react with acids to form salts and hydrogen gas:

  • General Equation: METAL + ACID → SALT + HYDROGEN

  • Completing word equations:

    • Magnesium + Nitric Acid → Magnesium Nitrate + Hydrogen

    • Iron + Sulfuric Acid → Iron Sulfate + Hydrogen

• Reactivity Variation: Not all metals interact with dilute acids; those below hydrogen in the series do not.

Displacement Reactions

• Definition: A more reactive metal displaces a less reactive metal from its compound.

• Example with Metal Oxides:

  • Mg + CuO → MgO + Cu (Magnesium displaces Copper)

• Observations: Color changes in solutions indicating reactions.

• Ionic Representation:

  • Ionic equations can demonstrate oxidation and reduction processes.

  • Oxidation: Loss of electrons (Zn in Zn + CuSO4)

  • Reduction: Gain of electrons (Cu2+ in Zn + CuSO4)

Properties of Metals in Reactivity

• Examples of usable metals and their behaviors:

  • Aluminium: Strong, low density, resistant to corrosion due to protective oxide layer.

• Halogen Reaction: Metals combine with halogens to form metal halides:

  • Example: Iron (III) Chlorine → Iron Chloride.

Class Exercises and Recap

• Question 1: Determine the reactivity order of metals based on their reactions with dilute hydrochloric acid.

• Question 2: Describe products formed when reacting alkali metals with water.

• Games for Reinforcement: Interactive quizzes on reactions of metals and displacement reactions.

• Diagrams: Summarize metal reactions with visual representations for easy reference.