Classifying Oxides (Cambridge International IGCSE Science)

Spec point — Classify oxides as acidic, including SO2 and CO2, or basic, including CuO and CaO, related to metallic and non-metallic character

Classifying oxides as acidic or basic

What are oxides?

• Oxides are compounds made from one or more atoms of oxygen combined with one other element

• Examples of oxides include:

  • Magnesium oxide - MgO
  • Zinc oxide - ZnO
  • Potassium oxide - K₂O
  • Carbon dioxide - CO₂
  • Sulfur dioxide - SO₂
  • Water - H₂O

• Oxides can be classified based on their acid-base characteristics

Acidic oxides

• Acidic oxides are formed when a non-metal element combines with oxygen

• Common examples include:

  • CO₂
  • SO₂
  • NO₂
  • SiO₂

Basic oxides

• Basic oxides are formed when a metal element combines with oxygen

• Common examples include:

  • CuO
  • CaO

Basic and acidic oxides

Metals form basic oxides while non-metals form acidic oxides