# How can I solve nuclear equations?

##### 1 Answer

Nuclear equations can be solved quite simply: let's do one example of alpha decay and one of beta decay.

#### Explanation:

First, a quick revision of radioactive decay:

During **alpha decay**, an alpha particle is emitted from the nucleus —- it is the equivalent of a helium atom (i.e. it has a mass of 4 and an atomic number of 2). So, let's take the following question:

**Polonium-210 is a radioisotope that decays by alpha-emission. Write a balanced nuclear equation for the alpha decay of polonium-210.**

In symbols, the equation becomes

The sums of the superscripts and of the subscripts must be the same on each side of the equation.

Take 4 away from the mass number (210-4 = 206)

Take 2 away from the atomic number (84-2 = 82). Lead is element number 82.

So, the equation is

Now let's try one for **beta decay** — remember that, in beta decay, a neutron turns into a proton and emits an electron from the nucleus (we call this a beta particle)

**Write a balanced nuclear equation for the beta decay of cerium-144**)

In nuclear equations, we write an electron as

Add one to the atomic number (58+1 = 59).

Don't change the mass number

Praseodymium is element 59

The answer is Pr-144.

Here's a **fission reaction**.

**A nucleus of uranium-235 absorbs a neutron and splits in a chain reaction to form lanthanum-145, another product, and three neutrons. What is the other product?**

We write a neutron as

Sum of superscripts on left = 236. Sum of superscripts on right = 148. So

Sum of subscripts on left = 92. Sum of subscripts on right = 57. So

The nuclear equation is