Nuclear physics might sound intimidating, but it's actually about understanding... Show more
Explore A-Level Physics: Particles and Radiation Topics

Fundamental Particles and Nuclear Structure
Every atom is built from three basic particles that you need to know inside out. Protons carry a positive charge (+1), neutrons are neutral (0 charge), and electrons have a negative charge (-1). What's fascinating is that protons and neutrons have nearly identical masses, but electrons are about 1,800 times lighter!
Isotopes are atoms of the same element that contain different numbers of neutrons. For example, uranium-238 and uranium-235 both have 92 protons, but different neutron counts. This difference in neutron number makes some isotopes unstable and radioactive.
The strong nuclear force is what holds the nucleus together despite protons trying to repel each other. It's one of four fundamental forces in nature and acts only over very short distances within the nucleus. Without this force, atoms would simply fall apart!
Nuclear notation uses the format ᴬzX, where A represents the mass number (total protons and neutrons), Z shows the atomic number (protons only), and X is the chemical symbol. This system lets you quickly identify any nucleus and its composition.
Key Insight: Understanding particle properties and nuclear notation is essential for tackling radioactive decay equations and nuclear reactions in your exams.
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Explore A-Level Physics: Particles and Radiation Topics
Nuclear physics might sound intimidating, but it's actually about understanding the tiny building blocks that make up everything around you. This topic covers the fundamental particles in atoms, how unstable nuclei change through radioactive decay, and the methods scientists use... Show more

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Fundamental Particles and Nuclear Structure
Every atom is built from three basic particles that you need to know inside out. Protons carry a positive charge (+1), neutrons are neutral (0 charge), and electrons have a negative charge (-1). What's fascinating is that protons and neutrons have nearly identical masses, but electrons are about 1,800 times lighter!
Isotopes are atoms of the same element that contain different numbers of neutrons. For example, uranium-238 and uranium-235 both have 92 protons, but different neutron counts. This difference in neutron number makes some isotopes unstable and radioactive.
The strong nuclear force is what holds the nucleus together despite protons trying to repel each other. It's one of four fundamental forces in nature and acts only over very short distances within the nucleus. Without this force, atoms would simply fall apart!
Nuclear notation uses the format ᴬzX, where A represents the mass number (total protons and neutrons), Z shows the atomic number (protons only), and X is the chemical symbol. This system lets you quickly identify any nucleus and its composition.
Key Insight: Understanding particle properties and nuclear notation is essential for tackling radioactive decay equations and nuclear reactions in your exams.
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Similar content
Most popular content: Alpha Particle
4Most popular content in Physics
9Most popular content
9Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.