Nuclear Equations
Nuclear equations balance mass numbers and atomic numbers.
About this topic
A nuclear equation shows changes to nuclei, with the sum of mass numbers and the sum of atomic numbers equal on both sides. For example, ²³⁸₉₂U → ²³⁴₉₀Th + ⁴₂He represents alpha decay. Beta decay is written with an electron, ⁰₋₁e, and gamma rays have no mass or charge.
Balancing a nuclear equation is like checking two ledgers: the top numbers (mass) must add up to the same total and the bottom numbers (charge or atomic number) must too. Identify the missing particle by subtraction. Because the number of protons changes in alpha and beta decay, one element is transformed into another, something ordinary chemical reactions cannot do.
Worked example: carbon-14 undergoes beta decay. The equation is 14 over 6 C giving 14 over 7 N plus 0 over minus 1 e. Mass: 14 = 14 + 0; charge: 6 = 7 + (-1). Carbon becomes nitrogen. Similarly, in positron emission a proton changes to a neutron and the atomic number drops by one.
These equations help predict decay chains such as uranium to lead, and power medical imaging and radiocarbon dating. A common mistake is forgetting that the electron in beta decay comes from the nucleus, not from the electron cloud, and that gamma emission leaves the nuclide unchanged.
Key ideas
- Alpha reduces Z by 2 and A by 4
- Beta increases Z by 1
- Total A and Z are conserved
Quick check
Use cases: where Nuclear Equations helps
- Homework: review the key idea behind Nuclear Equations before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Nuclear Equations without notes.
- Visual learning: play with the interactive lab to see how Nuclear Equations changes when you adjust its inputs.
- Teaching a friend: explain Nuclear Equations in your own words, then compare your version with the key ideas.
Chemistry explains medicine, food, cleaning products, fuels and building materials.
Frequently asked questions
What is Nuclear Equations?
Nuclear equations balance mass numbers and atomic numbers.
What will I learn in Nuclear Equations?
Alpha reduces Z by 2 and A by 4. Beta increases Z by 1. Total A and Z are conserved.
Is Nuclear Equations part of Chemistry?
Yes. It is one of 150 Chemistry topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Nuclear Equations lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Nuclear Equations?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.