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Edexcel IGCSE Chemistry · Spec 1.38-1.40

Ion Charges, Ionic Formulae and Dot-and-Cross Diagrams

Covers recall the required ion charges, Construct neutral ionic formulae and Draw dot-and-cross diagrams for unequal ion ratios.

Chemistry revision video

Ion Charges, Ionic Formulae and Dot-and-Cross Diagrams

Spec 1.38-1.40

What you need to know

  • Recall the required ion charges
  • Construct neutral ionic formulae
  • Draw dot-and-cross diagrams for unequal ion ratios

Active recall

Quick check

Answer each question before opening the answer.

What charge does sulfate carry?

2-

What is the formula of aluminium oxide?

Al2O3

Why are brackets used in (NH4)2SO4?

Because more than one polyatomic ammonium ion is needed

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