Elements, Compounds & Mixtures (Cambridge International IGCSE Science)

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Elements, compounds & mixtures

• All substances can be classified into one of these three types

  • Elements
  • Compounds
  • Mixtures

What is an element?

• A substance made of atoms that all contain the same number of protons and cannot be split into anything simpler by chemical means
• There are around 118 elements in the Periodic Table

What is a compound?

• A pure substance made up of two or more elements chemically combined
• There is an unlimited number of compounds
• Compounds cannot be separated into their elements by physical means
• E.g. copper(II) sulfate (CuSO₄), calcium carbonate (CaCO₃), carbon dioxide (CO₂)

What is a mixture?

• A combination of two or more substances (elements and/or compounds) that are not chemically combined
• Mixtures can be separated by physical methods such as filtration or evaporation
• E.g. sand and water, oil and water, sulfur powder and iron filings

Particle diagram showing elements, compounds and mixtures