Notes on Metals and Reactivity Series from IGCSE Chemistry

Introduction to Reactivity Series

  • The reactivity series ranks metals by their ability to react from most reactive to least reactive.
  • It includes metals and two non-metals (hydrogen and carbon) due to their roles in metal extraction.
  • Order of Reactivity Series:
    • Potassium
    • Sodium
    • Calcium
    • Magnesium
    • Aluminium
    • Carbon
    • Zinc
    • Iron
    • Hydrogen
    • Copper
    • Silver
    • Gold
  • Mnemonic for Recall: "Please Stop Calling Me A Cute Zebra, I Have Collected Shiny Gold."

Definition of Reactivity

  • Reactivity refers to how easily a metal can lose an electron to form a positive ion.
  • More Reactive Metals:
    • Lose electrons easily
    • Form positive ions readily
  • Less Reactive Metals:
    • Do not lose electrons easily
    • Form positive ions less readily

Displacement Reactions

  • Define Displacement Reaction: When a more reactive metal displaces a less reactive metal in a compound.
  • Example: More reactive magnesium can push out zinc, iron, copper, or silver from their compounds.
  • Observations: Displacement abilities confirm the metals' positions in the reactivity series.

Reactivity of Metals with Water

  • Highly Reactive Metals: React vigorously with cold water, producing a metal hydroxide and hydrogen gas.

    • Potassium: Reacts vigorously, producing potassium hydroxide and hydrogen, often igniting the hydrogen with a lilac flame.
    • Sodium: Reacts quickly but with less intensity than potassium, forming sodium hydroxide and hydrogen.
    • Calcium: Reacts slower with cold water, producing calcium hydroxide and hydrogen.

  • Less Reactive Metals:

    • Magnesium: Does not react with cold water but reacts with steam:
    • Reaction: Magnesium + Steam → Magnesium Oxide + Hydrogen

Reactivity of Metals with Acids

  • Metals react with dilute acids to produce a salt and hydrogen gas.
  • Magnesium: Reacts vigorously with dilute hydrochloric acid to produce magnesium chloride and hydrogen.
  • Zinc: Reacts moderately with dilute hydrochloric acid to produce zinc chloride and hydrogen.
  • Iron: Reacts slowly with dilute hydrochloric acid to produce iron(II) chloride and hydrogen.
  • Copper, Silver, Gold: These metals do not react with dilute hydrochloric acid because they are less reactive than hydrogen.

Deduction of Reactivity Order

  • To determine reactivity order, observe the speed/intensity of interactions with water, acids, and oxygen.
  • Rank metals based on the strength of these reactions.

Aluminum's Apparent Unreactivity

  • Aluminum forms a protective layer of aluminum oxide when exposed to air.
  • This oxide layer prevents it from reacting with water and acids, making it appear unreactive.

Conclusion

  • Knowing the reactivity series helps understand metals' behavior during reactions.
  • This knowledge is essential in predicting outcomes when working with various metals in chemical reactions.