Nuclear Decay


In this section :

As you’ve probably heard from a teacher, nuclear reactions are really important.  They’re important for people who are interested in blowing up large parts of the world, they’re important for people who are interested in making huge quantities of energy without creating huge quantities of pollution, and they’re important if you’re a doctor who wants to use radiation to treat various diseases.  See, it really is important.

In this help desk section, we’ll talk about the different types of radioactive decay!

Alpha decay


Alpha decay occurs when helium nuclei come flying off of the nucleus of a larger isotope, forming an isotope with a smaller mass.  These helium nuclei are called alpha particles, and are the same things that Rutherford busily shot at a sheet of gold foil during his experiment where he discovered the nucleus.  When an atom undergoes alpha decay, the atomic number of the atom decreases by two and the atomic mass decreases by four.  An example of alpha decay is shown below:

Beta decay


Beta decay is when an electron (called in this context a “beta particle”) is emitted from the nucleus of an atom, essentially turning a neutron into a proton.  As a result, the atomic number of the element increases by one, while the mass stays virtually unchanged.  An example of a beta decay is shown below:

Gamma decay


Gamma decay is when very high energy light called a gamma ray is emitted from a nucleus to bring it to a lower energy state.  Gamma decay generally takes place at the same time as other nuclear reactions:

Positron emission


Positron emission is when a positron is given off by a nucleus.  Positrons are the antimatter equivalent to electrons, so they have basically no mass and a charge of +1.  Positron emission causes the atomic number of the element to decrease and the atomic mass to stay unchanged:

Electron capture


Electron capture is when an electron is absorbed by the nucleus of an atom, causing the atomic number to decrease by one and the atomic mass to stay unchanged.  An example of an electron capture is shown below:

Questions, comments, interesting discoveries?  Share them with me via email at misterguch@chemfiesta.com