Radon is an inert gas that is generated in the soil when Radium decays.
It is the third major transformation in the radioactive decay of Uranium, and like its parents radon is a radioactive element. It has also been determined to be a factor in many lung cancers classified as a group carcinogen by the Environmental Protection Agency.
Radon is not the final stage in the Uranium-238 decay chain. Although it has a much shorter half life than Uranium and Radium, it breaks down in a mere three and one half days (3.7 precisely), it's decay gives birth to a group of elements which are known as the heavy metals, Polonium, Bismuth and Lead. These elements are called the radon daughters because they are brought into being by the existence of their parental element, radon.
Unlike radon, these elements are ionized. They have a charge and they readily attach themselves to various materials in the environment.
The health risk associated with radon is not from the radon gas. It is inert and does not re-act electro-chemically with the environment. The gas in its pure form can be inhaled into the lungs and exhaled with no ill effect. The health risk is actually associated with the radon daughters.
The radon daughters are also known as the heavy metals. They are charged particles, and tend to attach themselves to other particles in the environment. For the most part these particles have a very short half life. The principal radon daughters are Polonium-218, Bismuth-214, Lead-214, Polonium-214 and lead-210. The half-life of these elements is measured in seconds.
If you want to
understand this decay process more
thoroughly, look at the chart below and you can examine the radon decay chain in detail. Notice that each alpha decay changes the Atomic Weight while the beta decays changes only the atomic number.
