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← 1.3 The Periodic Table

The halogens

Chemistry · Grade 10 · about 40 minutes

Group VII: seven outer electrons, diatomic molecules, colour and state darken down the group, reactivity falls.

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  • 8 sections of explanation, worked examples and diagrams
  • 1 practice task with hints and worked answers
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Other lessons in this sub-strand

  1. Position and electron arrangement
  2. Ions, formulae and equations
  3. How the periodic table was invented
  4. Mendeleev's gaps and predictions
  5. Moseley and atomic number order
  6. Layout of the modern table
  7. Groups as chemical families
  8. Periods and electron shells
  9. The first twenty elements on the table
  10. Hydrogen's special position
  11. Metals, non-metals and metalloids
  12. What makes a metal
  13. What makes a non-metal
  14. The metalloid staircase
  15. The alkali metals
  16. The alkaline earth metals
  17. The halogens
  18. The noble gases
  19. The transition metals
  20. Trends in atomic radius
  21. Trends in ionisation energy
  22. Trends in melting point
  23. Trends in reactivity
  24. Soda ash and salt from Kenya
  25. Limestone and fluorspar
  26. Kenyan metal ores
  27. Predicting properties from position
  28. The table as a working tool