Fluorine, FLOO uh reen, is a chemical element. At ordinary temperatures, it is a pale yellow gas. Fluorine combines with other elements more readily than does any other element. Compounds that contain fluorine are called fluorides.
Krypton, KRIHP ton, is a chemical element that makes up only about one-millionth of Earth's atmosphere. The British chemists Sir William Ramsay and… More>>
Xenon, ZEE non or ZEHN on, is a chemical element that makes up about 1 part in 20 million of Earth's atmosphere. The British chemists Sir William… More>>
Chlorine, KLAWR een, is a poisonous, yellowish-green gas with a strong, unpleasant odor. Chlorine causes irritation to the nose, throat, and lungs.… More>>
Chlorine
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