Atoms and subatomic particles

This sub-topic introduces the fundamental structure of atoms, the key properties of protons, neutrons and electrons, and core notation for nuclides, ions…

📖Study Guide

In-depth bilingual notes with worked past paper examples.

✍️Practice Exam

Original questions for this topic: MCQ + FRQ + Application + drag/match.

🎴Flashcards

20+ flashcards: definitions / formulas / pitfalls. Click to flip.

📊Exam Insight Coming Soon

How this topic is distributed across past papers — data that shows what matters.

📊 Which Chemistry HL topics are most tested? See the real past-paper frequency →

Stuck on a specific question?
Snap a photo or paste your problem — Ollie (our AI tutor) walks through it step-by-step with diagrams.
Try Ollie free →