Chemistry Foundations

1.1.1 - Introduction to Particles

Introduction to Particles

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The word particle is used a lot in science courses.

For example, in Chemistry you learn that atoms are tiny particles, made up of even smaller particles called protons, neutrons and electrons. And you learn that in order for a chemical reaction to take place, the right particles must collide with each other with the right amount of energy. You also learn that solids, liquids and gases have their particles arranged in different ways.

However, despite the word particle being used in many science textbooks, they almost never explain what it means. Since it is such an important word in Chemistry, it seems like a good place to start this course.

Luckily, the meaning of the word particle is actually very simple.

A particle is a small object

Although particle sounds like a complicated sciencey word, all it actually means is 'a small object'.

There is no specific definition of how small something must be in order to count as a particle. In this course, most of the particles we will be looking at are very tiny - for example atoms and electrons.

However, sometimes the word particle can refer to bigger objects like a grain of sand or a piece of dust.

Since size is relative, what counts as a small object depends on the context. A physicist studying the formation of galaxies might even think of a star as a particle!

Many particles are too small to see

Most of the particles that we will learn about in this course are so small that they cannot be seen without special equipment. These include protons, neutrons, electrons, atoms, ions and molecules.

Diagrams of a proton, a neutron, an electron, an atom, an ion and a molecule.

Protons, neutrons, electrons, atoms, ions and molecules are all particles which are too small to be seen. In this course you will learn about all of these particles.

Subatomic particles are particles smaller than an atom

A subatomic particle is a particle which is smaller than an atom. There are many different types of subatomic particle. In this course, we will study three types: protons, neutrons and electrons.


Flashcards help you memorise information quickly. Copy each question onto its own flashcard and then write the answer on the other side. Testing yourself on these regularly will enable you to learn much more quickly than just reading and making notes.


What is a particle?


Are particles visible?


What is a subatomic particle?


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