The Helpful Chemist — Free GCSE Chemistry

Units and Scale

1 lesson · Getting to grips with scientific notation and orders of magnitude.

Getting a sense of scale

It's one thing to know atoms are small — it's another to truly feel the scale. This video takes you through a series of comparisons and calculations that make the size of an atom genuinely imaginable, from grains of sand to human hairs to the width of a nucleus. You'll also see how scientists use nanometres and standard form to express these measurements, and why scale matters across chemistry and nanotechnology.

▶ 1 video

The Particle Model

1 lesson · How particles explain the properties of solids, liquids and gases.

The Particle Model — Introduction

This is the starting point for understanding chemistry at a particle level. You'll meet the particle model — the idea that all matter is made of tiny spheres in constant motion — and see how it explains everything from why a liquid takes the shape of its container to why a puddle evaporates on a warm day. By the end you'll have the mental model you'll need for every topic in chemistry that asks for a particle-level explanation.

▶ 2 videos

Understanding Chemical Equations

2 lessons · Reading formulas and naming compounds.

Reading a chemical formula

Chemical formulae are the universal language of chemistry — and once you can read them, a whole new level of understanding opens up. This video teaches you a step-by-step method for decoding any formula: counting elements, reading subscripts, and working through brackets, finishing with the Co versus CO example that shows why capitalisation can mean the difference between cobalt and carbon monoxide. The foundation you need before tackling formula masses and balanced equations.

▶ 2 videos2 worksheets

Naming Compounds

Chemical names follow rules — and once you know those rules, you can name or identify any inorganic compound from its formula. This video walks you through the IUPAC naming system for binary compounds, acids, and compounds containing polyatomic ions, with enough worked examples to make the pattern stick. Ideal if you keep second-guessing whether something ends in -ide, -ate, or -ite.

▶ 2 videos2 worksheets

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