Organic chemistry is often described as the chemistry of life. It focuses on compounds built around the element carbon, and understanding it is essential not only for mastering IJSO questions but also for building a deeper appreciation of the molecular logic behind biology, medicine, and modern materials.
In this section, we’ll explore the foundation: what makes a compound organic, the types of basic organic compounds, and how we classify and understand them structurally and functionally. Our goal is not rote memorization, but to develop an instinctive grasp of patterns — the kind of insight that helps you work through unfamiliar molecules in competition settings with clarity and confidence.
At the most basic level, organic compounds are carbon-based molecules, typically containing carbon (C) and hydrogen (H), often alongside oxygen (O), nitrogen (N), sulfur (S), phosphorus (P), and halogens (F, Cl, Br, I).
Carbon’s unique ability to form four covalent bonds makes it capable of creating a stunning variety of molecular shapes: chains, rings, and branches.
Hydrocarbons are compounds made solely of carbon and hydrogen, and they are classified based on the types of bonds between carbon atoms:
Organic molecules with the same formula but different structures are called isomers
Understanding how atoms are arranged in space is critical in predicting chemical behavior.
Basic organic chemistry isn't about memorizing endless molecules. It’s about recognizing the familiar in the unfamiliar — seeing a hydroxyl and knowing it's an alcohol, spotting a double bond and expecting addition. For IJSO success, learn to connect structure to behavior, visualize molecular shapes, and think chemically.
You're not just preparing for a test — you're building a way of seeing the molecular world.
Written by Rand Ranj