Group 7: Oxidising Power, Displacement and Halide Tests · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Why halogens calm down down the group

Science · Chemistry · ages 16-17
Name ______________________   Date ____________

  1. You add chlorine water to a bromide solution. What happens?

    • Bromine is displaced and the solution darkens
    • Nothing happens at all
    • Chloride is displaced by bromine

  2. Why does oxidising power fall as you go down Group 7?

    • The nucleus loses protons down the group
    • Atoms get bigger and shielding grows, so the pull on a new electron weakens
    • The outer shell moves closer to the nucleus

  3. A white precipitate forms with silver nitrate and vanishes in dilute ammonia. Which halide is present?

    • Fluoride
    • Bromide
    • Chloride

  4. What does concentrated sulfuric acid make with sodium bromide?

    • Hydrogen chloride gas only
    • Bromine and sulfur dioxide alongside hydrogen bromide
    • Iodine, hydrogen sulfide and sulfur

  5. When chlorine displaces bromine, what is oxidised and what is reduced?

    • Chlorine is oxidised and bromide is reduced
    • Bromide ions are oxidised to bromine and chlorine is reduced to chloride
    • Both halogens are oxidised

  6. Yellow silver iodide dissolves away in concentrated ammonia.

    Circle one:   True   False

  7. A student predicts bromine will displace chlorine from a chloride solution. What is the error?

    • Bromine is the stronger oxidiser, so the prediction is actually right
    • Chlorine is the stronger oxidiser, so nothing happens
    • Chloride solutions always free any halogen

  8. Why does concentrated sulfuric acid give hydrogen chloride with sodium chloride but sulfur dioxide and iodine with sodium iodide?

    • The acid is weaker when it meets chloride
    • Chloride is more easily oxidised than iodide
    • Iodide is the most easily oxidised halide, so it reduces the acid while chloride cannot
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Why halogens calm down down the group W1-mt_li7olQ3dM9-s1

  1. Bromine is displaced and the solution darkens · Chlorine is the stronger oxidiser, so it forces bromine out as the free element.
  2. Atoms get bigger and shielding grows, so the pull on a new electron weakens · Bigger atoms with shielded centres pull weakly on incoming electrons.
  3. Chloride · White that clears in dilute ammonia is the chloride result.
  4. Bromine and sulfur dioxide alongside hydrogen bromide · Bromide reduces the acid partway, giving bromine and sulfur dioxide.
  5. Bromide ions are oxidised to bromine and chlorine is reduced to chloride · The loser gives up electrons and the stronger oxidiser gains them.
  6. False · Yellow silver iodide stays solid even in concentrated ammonia.
  7. Chlorine is the stronger oxidiser, so nothing happens · Displacement only runs from stronger to weaker, never the reverse.
  8. Iodide is the most easily oxidised halide, so it reduces the acid while chloride cannot · The halide gives up electrons more easily down the group, so the products get more reduced.
Worksheet · LightMySky