Early work on this topic usually centres around the language of inorganic complexes. Students learn about the meaning of 'ligand', how to write formulae for complexes and how to name them.

Simple class test tube experiments are a good way of introducing students to the concept of ligand exchange.

What test tube experiments might you ask students to carry out with aqueous copper sulfate solution and ammonia solution to reinforce the idea that an equilibrium is formed?

You could ask students to add excess ammonia solution to copper(II) sulfate solution and then add a lot of water to the mixture.

After the initial introduction, the topic can be broadened by including other copper complexes with monodentate ligands such as chloride ions and examples of complexes of other metal ions such as nickel and chromium.

Bringing in polydentate ligands such as 1,2-diaminoethane, ethanedioate and edta helps to develop the topic further. Now would be a good place to demonstrate a sequence of ligand exchange reactions.

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With the basic descriptive ideas in place students should have a secure understanding on which to build ideas about K_stab and the chelate effect.

The topic of inorganic complexes relies heavily on ideas that students will have met at different times and in different contexts during their studies. The activity below will give you an opportunity to reflect on what prior learning students need before they can understand this topic.

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