Period 3 element in 1810, who named it chlorine, from the Greek word χλωρος (chlōros), meaning "green-yellow." Chlorine is a component of various compounds, including table salt. It is the second most abundant halogen and 21st most abundant chemical element in Earth's crust. The great oxidizing potential of chlorine led it to its bleaching and disinfectant uses, as well as uses of an essential reagent in the chemical industry. As a common disinfectant, chlorine compounds are used in swimming pools to keep them clean and sanitary. In the upper atmosphere, chlorine-containing molecules such as chlorofluorocarbons have been implicated in ozone depletion. "Argon" (symbol
Shades of green Celtics of the National Basketball Association use this shade for their uniforms, logos and other memorabilia. "Tea green" is a light shade of green. It is a representation of the color of brewed green tea, i.e., the color of the hot green tea after the green tea leaves have been brewed in boiling water. The first recorded use of "tea green" as a color name in English was in 1858. "Teal" is displayed at right. It is a dark cyan color that is a representation of the color of the neck coloring of a duck called the common teal. Olive