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Grades 7 and 9 Intermediate About 15 min Version 1 Awaiting review Premium

Elements, compounds and mixtures

An element is made of only one kind of atom, such as iron (Fe) or oxygen (O₂). A compound is made of two or more kinds of atom chemically joined in a fixed ratio, such as water (H₂O); it has new properties and can only be split by a chemical reaction. A mixture contains two or more substances that are mixed but not chemically joined, such as air or salt water. The amounts in a mixture can vary, and it can be separated by physical methods like filtering, evaporating or using a magnet.

What you will learn

  • Describe elements, compounds and mixtures using particle models.
  • Explain the difference between a compound and a mixture.
  • Classify everyday substances.

Before you start

  • Know that matter is made of tiny particles called atoms.

Materials

  • Iron nail, copper wire, charcoal, oxygen, water, salt, sugar, carbon dioxide, air, salt water, muddy water, brass

Equipment

  • Particle model cards

Procedure

  1. Choose a card and look at its particle model.
  2. Check whether it can be separated by a physical method.
  3. Place each card in the elements, compounds or mixtures group.