Dot & Cross Diagrams

Specification Point 1.31:
  • Explain the formation of simple molecular, covalent substances, using dot and cross diagrams, including:
    a) hydrogen
    b) hydrogen chloride
    c) water
    d) methane
    e) oxygen
    f) carbon dioxide
  • Dot and cross diagrams are a quick and simple way to illustrate the atoms and electrons involved in simple covalent compounds.
  • Only the outer shells are included and dots and crosses are used to depict electrons donated from the different atoms.
  • If asked to draw a dot & cross diagram, write out the electronic configurations of the atoms first and count how many electrons there should be in total.
  • The bonding electrons should always be placed inside the overlap of the outer electron shells.
  • The nonbonding electrons should be placed in pairs exactly on the outer shells.
  • The nucleus of each atom should be represented by the chemical symbol of the element.
  • The table shows the names, formulae and dot & cross diagrams for the simple molecules which you need to know.

Dot cross diagram table, Edexcel GCSE Chemistry

Edexcel GCSE Chemistry Notes

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Morgan Curtin Chemistry

Author: Morgan

Morgan’s passion for the Periodic Table begun on his 10th birthday when he received his first Chemistry set. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid! In his spare time he helps create our fantastic resources to help you ace your exams.