Welcome to this deck on Atomic Structure, a fundamental topic in GCSE Chemistry. Everything around us is made of atoms. In this deck, you'll learn what atoms are made of, how to describe them using numbers, and how their internal structure determines their chemical properties. We'll cover the subatomic particles, atomic and mass numbers, isotopes, and the arrangement of electrons in shells.

At the heart of chemistry is the atom. For a long time, people thought atoms were the smallest possible things, tiny solid balls that couldn't be broken down. We now know that atoms themselves are made of even smaller particles. These are called subatomic particles, and there are three main types you need to know: protons, neutrons, and electrons.

The protons and neutrons are packed together in the centre of the atom, in a tiny, dense region called the nucleus. The electrons are not in the nucleus. Instead, they move around the nucleus in specific energy levels, which we often call shells.