Which of the following noble gases is radioactive and is produced as a decay product of radium?

💡 Solution & Explanation

Radon is a naturally occurring radioactive noble gas with no stable isotopes, formed during the radioactive decay series of radium. Argon, krypton, and xenon are stable noble gases present in trace quantities in the Earth atmosphere. Radon is dense, colorless, and odorless, posing health hazards in enclosed geological settings.