Properites

• Radon is a noble gas, meaning that it has very little or no reactivity with other compounds or elements, in addition to being both colorless and odorless. It is an element, is extremely unstable, and is identified on the Periodic Table as "Rn" with an atomic number (the number of protons in the nucleus) of 86. Its melting point is -96 F and its boiling point is -79 F, which is why it is almost always found on Earth in a gaseous state: despite being very heavy (heavier than iron), it is very rarely cold enough even in the coldest places on Earth to change radon into a liquid or a solid.
  
  

Radioactivity

• Because it is unstable, radon undergoes a process called radioactive decay. Atoms of this type decay by literally coming apart, with part of the atom's mass being ejected as radioactive particles and energy, and part of its mass remaining behind to become a new, lighter atom called a "daughter." Radon itself is usually the result of another element called radium decaying, and radon's daughter is polonium.
  
  

Location

• Radium is present in tiny quantities virtually throughout the Earth's crust. Since radon is a gas under all but the most extremely cold circumstances on Earth, when radium decays into radon, the gas is either emitted into the atmosphere or finds its way into the groundwater supply. This explains both its widespread presence in the environment, and why some natural springs are especially strong radon emitters. The Environmental Protection Agency (EPA) has charted the United States and rated individual counties on the predicted strength of local radon emissions, which varies across the country. For example, most of Maine is rated as having a potential to emit radon that is double or more than that of anywhere in Louisiana.
  
  

Danger

• Radon gas is most hazardous to humans because of its combination of radioactivity and weight. Since it is such an incredibly heavy gas, it has a natural tendency to collect in low, poorly ventilated places. A basement that has cracks in its floors and/or walls and little or no ventilation becomes a sump for concentrating radon and its accompanying radioactive emissions.
  
  

Statistics

• The EPA states that radon is the number one cause of lung cancer among non-smokers in America. That makes it the number two cause overall, and it is thought to be responsible for an estimated 20,000 deaths each year.