radon
/ˈɹeɪdɒn/
radon
English
Noun Top 40,501
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Definition
The chemical element (symbol Rn, formerly Ro) with atomic number 86. It is an odorless, colorless, chemically inert but radioactive noble gas.
Etymology
Contraction of radium emanation, since the element appears in the radioactive decay of radium. By surface analysis, radio- + -on (“suffix for noble gases”).
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