Try this lesson plan for 16–18 year olds to support your students to research transition metal complexes, including shape, naming, bonding and ligand exchange

In this activity, students work in small groups and follow given guidelines to research one of four aspects of transition metal complexes. They then teach others about their topic and are taught in turn by other students about the other three aspects.

Learning objectives

Students will understand:

  • What transition metal complexes are.
  • How to name them.
  • What shapes they have.
  • About the process of ligand exchange.

Sequence of activities

Introduction and demonstration

Use a demonstration to explain the purpose of the session.

An example of ligand exchange can be demonstrated by adding ammonia solution to copper(II) sulfate solution in a large conical flask, or by adapting the first part of a procedure that uses test tubes for observing an equilibrium involving copper(II) ions.

Activity: stage 1

  1. Give each student a copy of ‘Guidelines for the work in groups’.
  2. Allocate one of the ‘Expert’ topics a, b, c or d to each student. The topics offer a range of challenges that give the opportunity to differentiate by task.
  3. Make available and/or direct students to resources that they can use to research their allocated topic.

Activity: stage 2

Arrange students into topic groups a, b, c or d. These will become ‘Expert’ groups.

Circulate and support with prompts while students:

  1. Individually research their topic.
  2. As a group, discuss what and how they will teach other students, using the ‘Guidelines for the work in groups’.
  3. Prepare brief notes, diagrams and questions to help them teach their topic.

Activity: stage 3

Reorganise the students into groups of four comprising one member from each ‘Expert’ group. These are the ‘Teaching’ groups.

Circulate and support, if needed, while students:

  • Take turns to explain the topic for which they are the ‘Expert’.
  • Make notes about the topics they have not prepared to accompany the notes they have made on their ‘Expert’ topic.


Ask the students to hand in their notes. Acknowledge achievement and provide comment that leads students to carry out additional work or to move forward.


The extent of the learning objective is made clear with the help of the ligand exchange demonstration.

When the students are working in their ‘Expert’ group they evaluate their learning, through sharing information and questioning their colleagues. In ‘Teaching’ groups, the students pose questions (to which they should know the answers) but, also, their own understanding of the topic is tested by questions from the other members of the group.

The teacher provides written feedback on the notes students have made to acknowledge achievement and to provide comment that leads students to recognise their next steps and how to take them.

Practical notes

A procedure for demonstrating an example of ligand exchange may be adapted from a class experiment in which ammonia solution is added to copper(II) sulfate solution to observe an equilibrium. Alternatively, the teacher can follow a similar procedure using the apparatus and chemicals specified below.


  • Eye protection
  • Conical flask, 500 cm3


  • Copper(II) sulfate solution, 0.1 mol dm-3
  • Ammonia solution, 2 mol dm-3

Health, safety and technical notes

Other equipment

For each student:

  • Mini whiteboard
  • Access to resources to research transition metal complexes