5.4 Chemical changes

Unit Summary

This unit is aligned with the AQA GCSE Combined Science: Trilogy specification and is designed to be sequenced flexibly. However, it is structured with the assumption that each year builds upon the knowledge and skills developed in previous units.

Both substantive knowledge (scientific content) and disciplinary knowledge (working scientifically) are taught in context, ensuring that key scientific principles are reinforced through practical application. This Chemical Changes unit covers essential content including reactivity of metals, metal-acid reactions, the reactivity series, ionic equations, oxidation and reduction, and methods of extracting and purifying metals. Students will also investigate the pH scale, acid-alkali reactions, neutralisation, and the preparation of salts, developing practical skills through techniques such as salt crystallisation.

The unit incorporates hierarchical elements of working scientifically, enabling pupils to progressively develop their investigative skills, including planning, observation, data recording, analysis, and evaluation. While it builds on prior learning from earlier key stages—such as basic particle models and simple reactions—support structures and scaffolds are embedded to ensure accessibility for all learners.

To support ongoing assessment and deep learning, a variety of Assessment for Learning (AfL) strategies are embedded within each lesson. These include retrieval practice, diagnostic questioning, and structured activities that address misconceptions, reinforce key concepts, and promote long-term knowledge retention.

Developing Experts is committed to supporting schools in delivering the National Curriculum effectively. While curriculum design is guided by National Curriculum content, we also extend beyond these requirements to provide greater challenge and aspiration. This is achieved by linking scientific concepts to real-world applications, especially those related to careers in chemical engineering, pharmaceuticals, environmental science, and industrial processes, helping students connect classroom learning to the wider world of work.