Radon

Symbol: Ra
Atomic number: 86
Category: noble gases
Group: 18
Period: 6
Block: p
Atomic weight: (222) g/mol
Electrons per shell: 2, 8, 18, 32, 18, 8
CAS number: 10043-92-2
Phase: gas
Density: 9.73 g/l (0C, 101.325 kPa)
Melting point: 202 K (-71.15C, -96F)
Boiling point: 211.3 K (-61.85C, -79.1F)
Crystal structure: cubic face centered
Oxidation states: 0
Electronegativity: 2.2 (Pauling scale)
Name's origin: radium emanation
Name's meaning: a shortened version of the phrase - emanation is from the Latin word 'emanatio' (expiration)
Facts:
- is a colorless, odorless, tasteless, naturally occurring, radioactive noble gas that is formed from the decay of radium
- is one of the heaviest substances that remains a gas under normal conditions and is considered to be a health hazard
- the most stable isotope, radon-222, has a half- life of 3.8 days
- will continue to exist indefinitely at about the same levels as it is now
- is responsible for the majority of the mean public exposition to ionizing radiations, it is often the single largest contributor to an individual's background radiation dose
- is reportedly the second most frequent cause of lung cancer, after cigarette smoking; and radon- induced lung cancer the 6th leading cause of cancer death overall
- the radon itself isn't very dangerous, but its radioactive decay products are - polonium-218 and 214 - which remain lodged in the lungs, and continue to decay, causing continued exposure by emitting alpha radiations