라듐이 붕괴할 때 생기는 무색, 무취의 방사성 기체 원소로, 원자 번호는 86, 기호는 Rn이다.
A radioactive, colorless, odorless, tasteless noble gas, occurring naturally as an intermediate step in the normal radioactive decay chains.
예문:
"The geologist measured the concentration of radon in the soil to monitor seismic activity."
"Radon can accumulate in poorly ventilated basements, reaching dangerous levels over time."
"Because it is a noble gas, radon is chemically unreactive under most standard conditions."