Electron Configuration

Build orbital diagrams, discover periodic-table patterns, form common ions, and solve electron-configuration challenges for first-semester general chemistry.

Features

• Fill the Orbitals: an energy-staircase orbital diagram you edit directly (click to cycle, drag electrons from a tray or between orbitals, U/D/Delete on the keyboard), Pauli shake, per-subshell feedback after Check, undo, and guided filling.
• Patterns in the Table: a block-coloured table (H–Rn, with the lanthanide row) with hover preview, "Step through the table" autoplay that pauses on the ground-state exceptions (Cr, Cu, Nb–Ag, La, Ce, Gd, Pt, Au), observed vs. filling-rule notation, and inner/outer shell counts.
• Make an Ion: twenty-five common ions (from Na⁺ to Pb²⁺), proton/electron tallies, electrons animated to and from the surroundings (4s empties before 3d), and a neutral comparison.
• Configuration Detective: eight repair, move-the-misplaced-electron, identify, isoelectronic, and classification challenges, with large answer tiles and a star per solved challenge.
• Block-tinted configuration chips, an optional count-by-shell view, rules in per-screen info dialogs, English/French/Spanish, keyboard access, live screen summaries, projector colors, and portrait scrolling.

This is a symbolic occupancy model. It checks introductory configuration and Hund patterns, not complete atomic term states. See model and sources.

Quick Start

Requires Node 26 or later.

npm ci
npm start

Elements run H–Rn by default. Use Preferences → Simulation or ?maxZ=36 (through Kr) / ?maxZ=54 (through Xe) to limit the table, as in PeriodicTrends. Use ?z=26 to start the neutral exploration at iron. Standard SceneryStack parameters include ?locale=fr, ?colorProfile=projector and ?screens=2.

Scripts

• npm run check — TypeScript checks.
• npm run lint / npm run fix — Biome checking and fixes.
• npm test — chemistry, model actions and disposal regressions.
• npm run build / npm run build:single — production PWA / single HTML build.
• npm run test:fuzz:quick — short browser fuzz test.
• npm run icons — generate icons from the source SVG.

Tech Stack

TypeScript 7, SceneryStack 3, Vite 8, Vitest, Playwright, and Biome. Created from SceneryStackTemplate.

License

AGPL-3.0-or-later. See the OpenLyceum license.

Contributing

See OpenLyceum contribution guidance and AGENTS.md. Preserve the model scope and extend independent chemistry fixtures when adding species.