Covalent Bonds: Dot & Cross Diagrams (Edexcel IGCSE Science (Double Award))

Revision Note

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Dot and cross diagrams for covalent compounds

  • Covalent substances tend to have simple molecular structures, such as Cl2, H2O or CO2

  • These small molecules are known as simple molecules

  • Small covalent molecules can be represented by dot and cross diagrams

  • You need to be able to describe and draw the structures of the molecules below: 

Diatomic Molecules

Dot-&-cross-Hydrogen_, IGCSE & GCSE Chemistry revision notes

Dot & cross representation of a molecule of hydrogen

Dot-&-cross-Chlorine_, IGCSE & GCSE Chemistry revision notes

Dot & cross representation of a molecule of chlorine

Dot & Cross Oxygen, IGCSE & GCSE Chemistry revision notes

Dot & cross representation of a molecule of oxygen

Dot & cross Nitrogen, IGCSE & GCSE Chemistry revision notes

Dot & cross representation of a molecule of nitrogen

Dot & cross Hydrochloric-Acid, IGCSE & GCSE Chemistry revision notes

Dot & cross representation of a molecule of hydrogen chloride

Inorganic Molecules

Dot & cross Water, IGCSE & GCSE Chemistry revision notes

Dot & cross representation of a molecule of water

Dot & cross Ammonia, IGCSE & GCSE Chemistry revision notes

Dot & cross representation of a molecule of ammonia

Dot-&-cross-Carbon-Dioxide_, downloadable IGCSE & GCSE Chemistry revision notes

Dot & cross representation of a molecule of carbon dioxide

Organic Molecules

Dot & cross Methane, IGCSE & GCSE Chemistry revision notes

Dot & cross representation of a molecule of methane

Ethane Dot & Cross Diagram, downloadable IGCSE & GCSE Chemistry revision notes

Dot & cross representation of a molecule of ethane

Dot-&-cross-Ethene_, IGCSE & GCSE Chemistry revision notes

Dot & cross representation of a molecule of ethene

Examiner Tips and Tricks

Each covalent bond represents one shared pair of electrons. 

For example, there are two covalent bonds between the two oxygen atoms in O2 so four electrons are shared.

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