How do you complete the following alpha decay reaction?

1 Answer
Jul 2, 2016

23290Th22888Ra+42He

Explanation:

The general notation of a nuclide (X) is:

AZX

In wich Z is the number of protons and A the mass number (protons + neutrons).

In alpha decay the nucleus emits a particle that contains 2 protons and 2 neutrons, which is similar to the nucleus of helium. So a notation for the nuclide (Y) that is left after emitting an alpha particle (42He) is:

A4Z2Y+42He

Now you can complete the equation given in the example:

228+488+2X=23290X

The last step is finding the nuclide that has 90 protons and 142 neutrons in a table of nuclides. This appears to be Thorium (Th).

This makes the equation complete:

23290Th22888Ra+42He