This interactive educational resource package is designed for the Scottish National 3 Science and National 4 Chemistry curriculums, directly supporting the Atomic Structure & Chemical Changes units. The core component is an offline-capable, standalone digital app (atomic-structure-builder.html) that allows pupils to tap any of the first 20 elements to dynamically view its Bohr model, particle counts, and electron configuration, or test themselves using a built-in multiple-choice quiz mode. Alongside the digital builder, the package includes a 20-mark pupil recording sheet (atomic-structure-recording-sheet.pdf) to guide students through data collection, core conceptual questions, and self-assessment, a matching teacher mark scheme (atomic-structure-mark-scheme.pdf) with complete grading guidance and suggested grade boundaries, and a clean, modern cover image (atomic-structure-cover.png) to complete the resource pack.