1. Each element has a different symbol
Chemical Formula
Each element has a different symbol
The formula for a compound shows the elements in the compound
It also shows the ratio of the atoms of different elements in the compound
Chemical Formula

2. The Periodic Table
The Periodic Table

3. Chemical Formula
Chemical Formula

4. Atomic Structure
Atomic Structure

5. Electron shells
Electron shells

6. Electron shells
Electron shells

7. Word equations
Word equations use the names of the reactants and products to describe a reaction
Word equations

8. Word equations
Word equations

9. Therefore chemical equations must be balanced
Chemical equations use the chemical formulae of the reactants and products to describe a reaction
The total mass of the product(s) of a chemical reaction must equal the total mass of the reactant(s)
Therefore chemical equations must be balanced
The total number of atoms of one element should be the same on both sides of the equation
Chemical equations

10. Balancing equations
Balancing equations

11. Relative atomic masses
Atoms of different elements have different masses
The relative atomic mass (Ar) is the mass of the elements compared to the mass of a hydrogen atom
Relative atomic masses

12. Relative atomic masses

13. Relative Formula Mass
The relative formula mass (Mr) is the relative mass of a molecule compared to the mass of a hydrogen atom
Relative formula mass

14. Relative formula mass
Relative formula mass

15. Equation calculations
The unknown mass of a reactant or product can be worked out by using the known masses of the other reactants and products
Equation calculations

16. Calculations from equations

17. Calculations from equations