Particles Builder: Elements, Compounds and Mixtures is an interactive particle-modelling tool designed to help students use key chemistry vocabulary accurately. Teachers or students can drag different types of atoms into a container and move them together to form molecules. Atoms snap together when brought sufficiently close, allowing users to quickly construct particle diagrams representing elements, compounds and mixtures. The tool automatically analyses the particles in the container and can reveal the most appropriate description, such as: atoms of a single element molecules of a single element molecules of a compound a mixture of atoms of different elements a mixture of elements and compounds a mixture of different compounds This makes the tool particularly useful for developing students’ understanding of the differences between atoms, molecules, elements, compounds, particles and mixtures, while also allowing rapid questioning and self-checking. simopsis