# Episode 512: Nuclear equations

Now that your students are familiar with different types of radiation, you can look at the processes by which they are emitted.

**Summary**

- Discussion: Nuclide notation and
*N*-*Z*plot (10 minutes) - Student Questions: Practice with notation (10 minutes)
- Worked Examples: Equations for alpha, beta and gamma decay (20 minutes)
- Student Questions: Practice with nuclear equations (30 minutes)

**Discussion: Nuclide notation**

Revise nuclide notation:

Discuss how *A* = mass or nucleon number, *Z* = charge or atomic number and *N* = neutron number are related (*A* = *Z* + *N*).

Discuss isotopes (common examples: H, D and T, U-235 and U-238, C-14 and C-12).

Set the task of finding out the name for nuclides having the same A but different Z (isobars), and the same *N* but different *Z* (isotones).

Show an *N*-*Z* plot (Segrè plot).

**Student questions: Practice with notation**

Set some simple questions involving nuclide notation.

Episode 512-1: Nuclide notation (Word, 36 KB)

Grid showing change in A and Z with different emissions

**Worked examples: Equations for alpha, beta and gamma decay**

Nuclear decay processes can be represented by nuclear equations. The word **equation** implies that the two sides of the equation must ‘balance’ in some way.

Episode 512-2: Decay processes (Word, 53 KB)

You could give examples of equations for the sources used in school and college labs.

a sources are americium-241,

b^{-} sources are strontium-90,

The underlying process is:

n –> p + e^{-} + n

Here, n is an antineutrino. Your specification may require you to explain why this is needed to balance the equation.

You can translate n –> p + e^{-}_{ } into the AZ notation:

γ sources are cobalt-60 . The γ radiation comes from the radioactive daughter of the β decay of the . The is formed in an ‘excited state’ and so almost immediately loses the energy by emitting a g ray. They are only emitted after an α or β decay, and all such γ rays have a well-defined energy. (So a cobalt-60 source which is a pure gamma emitter must be designed so that betas are not emitted. How? – (by encasing in metal which is thick enough to absorb the betas but which still allows gammas to escape.)

**Student questions: Practice with nuclear equations**

Episode 512-3: Practice with nuclear equations (Word, 66 KB)

The more unusual decay processes (positron emission, neutron emission, electron capture) could be included, and students challenged to write them as nuclear equations.

**Download this episode**

Episode 512: Nuclear equations (Word, 180 KB)