The Element: Chlorine General Information We researched the chemical element known as chlorine. Chlorine has an atomic number of 17 and an atomic weight of 35.453. It has a valence number of 3. The element has 3 energy levels. Chlorine exists as a greenish-yellow gas at normal temperatures and pressures. Chlorine is second in reactivity only to fluorine among the halogen elements. Chlorine is a nonmetal. It is estimated that 0.045% of the earth's crust and 1.9% of sea water are …showed first 75 words of 1165 total…

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