Chemical FormulaEach element has a different symbolThe formula for a compound shows the elements in the compound It also shows the ratio of the atoms of different elements in the compoundChemical Formula

The Periodic TableThe Periodic Table

Chemical FormulaChemical Formula

Atomic StructureAtomic Structure

Electron shellsElectron shells

Electron shellsElectron shells

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

Word equations

Word equationsWord equations

Chemical equationsChemical equations use the chemical formulae of the reactants and products to describe a reactionThe total mass of the product(s) of a chemical reaction must equal the total mass of the reactant(s)Therefore chemical equations must be balancedThe total number of atoms of one element should be the same on both sides of the equationChemical equations

Balancing equationsBalancing equations

Relative atomic massesAtoms of different elements have different massesThe relative atomic mass (Ar) is the mass of the elements compared to the mass of a hydrogen atomRelative atomic masses

Relative atomic massesRelative atomic mass

Relative formula massThe relative formula mass (Mr) is the relative mass of a molecule compared to the mass of a hydrogen atomRelative Formula Mass

Relative formula massRelative formula mass

Equation calculationsThe unknown mass of a reactant or product can be worked out by using the known masses of the other reactants and productsEquation calculations

Calculations from equationsCalculations from Equations

Calculations from equationsCalculations from Equations