At -50 0C radon is a gas.
Gaseous state. The boiling point of radon is -71 degrees C. So at 20 degrees C, it is above the boiling point and is a gas at this temperature.
In its gaseous state it is colorless, but when it freezes at -71°C the cooled, solid radon emits a pale yellow light. On intense cooling, it glowswith a orangish color.
Radon is a gas at room temperature, and quite a bit below it, too. A link can be found below.
Radon is a natural radioactive gas.
At room temperature radon is a gas.
Radon is everywhere in the world, but its concentrations in air are very different.
The state depends on the temperature and pressure. At STP, radon is a gas.
The element, Radon is one of the Noble Gases like Helium and Neon that do not form compounds. Thus Radon is always found in the Pure State.
Radon (Rn) Melting points: 202.0 K, −71.15 °C, −96.07 °F Boiling points: 211.3 K, −61.85 °C, −79.1 °F
One can order a radon testing kit from stores such as Lowes or Walmart. One can also order a radon testing kit by contacting one's state radon contact.
You can purchase do-it-yourself radon testing kits for between $10 and $50. Having someone else test for you will cost between $50 and $150, so if you can, do it yourself.
Radon is one of the noble gasses. As such, it exists naturally in its elemental state and does not easily form compounds.