5.2 Bonding, structure, and the properties of matter

Unit Summary

This unit is aligned with the AQA GCSE Trilogy specification and is designed for flexible delivery. It assumes that learners build progressively on knowledge and scientific enquiry skills developed in earlier units and key stages.

The unit integrates both substantive knowledge (core scientific ideas) and disciplinary knowledge (working scientifically), ensuring that students learn key principles through context-based investigations and real-world applications. At the heart of this unit is the understanding that the physical and chemical properties of substances can be explained by their structure and bonding. Students learn how atoms can be held together by ionic, covalent, or metallic bonds, and how these bonds give rise to very different structures, ranging from small simple molecules to giant lattices and metallic crystals.

Through this lens, students examine why substances behave as they do—why some have high melting points, why some conduct electricity, and why others are brittle, flexible, or soluble. Practical and model-based activities help students connect particle-level theories to observable properties, deepening their ability to explain real materials and their uses. The unit also introduces nanoparticles, polymers, and composites, showing how scientists engineer new materials with desirable properties.

Explicit links are made to real-world applications: students explore how knowledge of structure and bonding underpins technologies from construction materials to electronics, and how it drives innovation in fields such as nanotechnology and medicine. Careers in chemical engineering, product design, and materials science provide context for how this knowledge translates beyond the classroom.

Working scientifically is embedded throughout, with opportunities for pupils to plan and carry out experiments, construct and interpret particle models, and analyse data to explain observed properties. Scaffolds support accessibility for all learners while addressing misconceptions—for example, that ionic compounds conduct electricity in all states, or that simple covalent molecules have strong intermolecular bonds.

To promote deep and long-term learning, a variety of Assessment for Learning (AfL) strategies are woven into lessons, including retrieval practice, diagnostic questioning, model evaluation, and structured discussion. These approaches reinforce conceptual understanding, promote metacognition, and encourage students to connect ideas across the curriculum.

In addition to meeting National Curriculum requirements, this unit extends learning by highlighting how chemists apply bonding theories to engineer new materials and solve practical challenges. By exploring the connections between atomic structure, material properties, and technological applications, students gain insight into both the explanatory power of chemistry and its societal and industrial relevance.