Complex Ions, Ligands and Their Shapes · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Ligands, shapes and isomers

Science · Chemistry · ages 17-18
Name ______________________   Date ____________

  1. What is the coordination number of [Cu(H2O)6]2+?

    • 2
    • 4
    • 6

  2. What is a ligand?

    • A particle that donates a lone pair to a metal
    • A metal that donates electrons to water
    • A salt that never dissolves

  3. Cisplatin, the cis form, fights tumours while the trans form does not.

    Circle one:   True   False

  4. Which ligand is bidentate?

    • Water
    • Ethane-1,2-diamine
    • Chloride

  5. Why does [CuCl4]2- take a tetrahedral shape instead of octahedral?

    • Chloride ligands are too bulky for six to fit
    • Copper cannot form octahedral shapes at all
    • Tetrahedral is always the strongest shape

  6. Why do bidentate complexes hold on more tightly?

    • They contain more metal ions
    • The double chelate grip resists being pulled apart
    • They dissolve faster in water

  7. A new square planar drug works only as the cis form. A student says the trans form is worth testing as the same drug. What is the flaw?

    • Trans forms are always poisonous to make
    • Shape can decide drug action, as cisplatin versus trans shows
    • Cis and trans are the same shape with two names

  8. A student labels [CuCl4]2- as octahedral with coordination number 6. What is wrong?

    • Nothing, since all copper complexes are octahedral
    • It holds 4 chlorides, so the number is 4 and the shape is tetrahedral
    • It holds 4 chlorides, so the number is 2 and the shape is linear
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Answer key

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

Ligands, shapes and isomers W1-mt_xxWYYqgZp_-s1

  1. 6 · Six waters each bond once, so the count is 6.
  2. A particle that donates a lone pair to a metal · A ligand gives its lone pair into an empty metal orbital.
  3. True · The shape decides the drug action. The sentence is true.
  4. Ethane-1,2-diamine · Ethane-1,2-diamine binds through two atoms. The others bind through one.
  5. Chloride ligands are too bulky for six to fit · Four bulky chlorides fit tetrahedrally, while six small waters fit octahedrally.
  6. The double chelate grip resists being pulled apart · Two bonds per ligand mean the ligand must lose both grips at once to leave.
  7. Shape can decide drug action, as cisplatin versus trans shows · Cisplatin proves the point: the cis form fights tumours and the trans form does not.
  8. It holds 4 chlorides, so the number is 4 and the shape is tetrahedral · Four ligands give coordination number 4, and bulky chlorides arrange tetrahedrally.
Worksheet · LightMySky