Nuclear Equations [H]

This lesson covers nuclear equations as required by the AQA GCSE Physics specification (4.4.2). This is Higher Tier only content, indicated by [H]. You need to be able to write and balance nuclear equations for alpha decay, beta decay, and gamma emission, and to use these equations to identify unknown products.

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What Are Nuclear Equations?

A nuclear equation represents a radioactive decay process. It shows the parent nucleus (the original unstable nucleus), the daughter nucleus (the new nucleus formed after decay), and the radiation emitted.

In nuclear equations, each nuclide is written with its:

• Mass number (A) as a superscript (top number)
• Atomic number (Z) as a subscript (bottom number)

The key rule for balancing nuclear equations is:

The total mass number (A) on the left must equal the total mass number on the right. The total atomic number (Z) on the left must equal the total atomic number on the right.