Today, chlorine is mostly obtained by electrolysis of sodium chloride solutions. Seawater and the Sun also contain certain quantities of chlorine in its elemental form. This yellow-green gas is also released by volcanoes, forest fires, and some plants. Chlorine is released in the atmosphere from the ocean algae in a form of methyl chloride. This chemical element can be naturally found in inorganic chlorinated substances (such as sodium chloride, or table salt), as well as in organochlorines. These elements are considered to be the basic building blocks of our planet, as well as the life on it. Where Can You Find Chlorine?Ĭhlorine belongs to the group of chemical elements that can be found in their elemental form in nature, counting approximately a hundred of them. This chemical element was named in 1810 by Sir Humphry Davy. The name of the chemical element chlorine comes from the Greek word “khloros” that literally depicts the green color of chlorine’s pure elemental form. The English chemist also managed to determine the properties of the newly established chemical element. Several decades later, in 1810 to be more precise, the English chemist Sir Humphry Davy (1778 – 1829) gave more attention to this compound, and by conducting his experiments on what was believed to be dephlogisticated marine acid, Sir Davy succeeded in affirming chlorine as a new chemical element by proving that there is no oxygen in the compound. He firmly believed that what he had in front of him was a compound of oxygen, which he called ‘a dephlogisticated marine acid’. However, Scheele didn’t realize that he had just discovered a new chemical element. In an instant, a greenish-yellow gas was released from the chemical mixture. Namely, in 1774, the Swedish pharmacist Carl Wilhelm Scheele (1942 – 1786) attempted an experiment by causing a reaction between hydrochloric acid with manganese dioxide. And, like almost all great inventions and discoveries of the modern times, chlorine was discovered after an oversight. Traces of the chlorine compounds that are nowadays extensively used in the industries (pentachlorophenol, polychloropyrols, polychlorinated biphenyls (PCB), and tetrachlorodibenzodioxins (TCDD)) have been found in rock sediments as old as 8,000 years. Apart from adopting highly corrosive properties, chlorine makes for a strong acid and an oxidizer in the presence of water molecules that readily attacks rubber, plastic, and various metals. Highly reactive with water (H 2 O), chlorine also becomes very corrosive when combined with H 2 O molecules.
Namely, when chlorine is compounded with bases, turpentine, ammonia, fuel gas, hydrogen, fluorine, and organic compounds, it poses a potential risk of fire or explosion. This member of the halogen family of elements in the periodic table has an electronegativity of 3.16 according to Pauling, whereas the atomic radius according to van der Waals is 0.127 nm.ĭespite being a non-flammable gas in its elemental form, chlorine reacts in a volatile and explosive manner due to its combustion-enhancing properties. įurthermore, chlorine reaches its boiling point at -34.6 ☌, while the melting point of this gas is achieved at -101 ☌. The solid form of chlorine occurs as calcium hypochlorite. It changes from a gaseous aggregate state into a liquid under pressure. Having an atomic mass of 35.45 g.mol -1 and electron configuration 3s2 3p5, chlorine is a chemical element that is heavier than air. The energy of the third ionization: 3822 kJ.mol -1ĭiscovery date: In 1774 by Carl Wilhelm Scheeleĭiatomic in nature (occurring as Cl 2 ), this yellow-green gaseous element with a pungent, irritating odor carries the symbol Cl and the atomic number 17 in the periodic table of elements. The energy of the second ionization: 2298 kJ.mol -1 The energy of the first ionization: 1255.7 kJ.mol -1 Most characteristic isotope: 35 Cl, 36 Cl, 37 Cl
Half-life: From less than an hour, up to 301,300 ± 1,500 yearsĮlectronegativity according to Pauling: 3.16 The symbol in the periodic table of elements: (Cl)Ĭolor: Pale greenish-yellow gas at a room temperature / Clear, amber-colored liquid under applied pressure or at temperatures below -30☏ (-34☌) Fact Box Chemical and Physical Properties of Chlorine Being a member of the halogen family of periodic table elements, chlorine is a highly reactive chemical substance with seven valence electrons in its outer shell. It’s the twentieth most abundant element found in Earth’s crust, amounting to 130 ppm or 0.01 percent. Chlorine is a chemical element with an atomic number of 17 in the periodic table of elements.
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