Lesson 2 of 8

Atoms rearrange

Goal: Describe a reaction as atoms rearranging.

Puzzles for this lesson

Methane burning, as a particle diagram. Each circle is an atom: C is carbon, H is hydrogen and O is oxygen. Count them on each side of the arrow.

In a chemical reaction the atoms are rearranged. They leave their old partners and join up in a new way.

Reactants are the substances you start with. Here they are methane and oxygen.
Products are the new substances that are made. Here they are carbon dioxide and water.
No atom is made and no atom is destroyed. Every atom in the reactants ends up in one of the products: here, 1 carbon, 4 hydrogen and 4 oxygen atoms.

Your turn

This lesson’s activity starts here in a moment.

I can name the reactants and products.I can show a reaction with a particle diagram.

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Chemical reaction A change in which a new substance is made

Reactant A substance you start with in a reaction

Product A new substance made in a reaction

For teachers: AQA 3.6.4 · Pearson Edexcel 14.2, 23.1 · Cambridge 7Cc.03