Chemical element and Radon

Chemical element noun - Any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter.

Radon and chemical element are semantically related. In some cases you can replace term "Radon" with "Chemical element", this terms are similar.

Radon noun - A radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to health.

Chemical element and radon are semantically related. You can use "Chemical element" instead a noun "Radon".