Like all halogens, chlorine - p-element, a typical non-metal, under normal conditions exists in the form of diatomic molecules.The outer layer of the electronic chlorine atom has one unpaired electron, so it is characterized by a valence I. In the excited state number of unpaired electrons can be increased, so the chlorine can be also valence III, V and VII.
Cl2 under normal conditions - a poisonous yellow-green gas with a characteristic pungent odor.It is heavier than air 2.5 times.Inhalation of chlorine, even in small quantities, leads to irritation of the respiratory and cough.At 20 ° C in a volume of water is dissolved 2.5 gas volume.The aqueous solution of chlorine bleach called water.
chlorine hardly occurs
in nature in free form.It is distributed in the form of compounds: sodium chloride NaCl, sylvite KCl ∙ NaCl, KCl ∙ MgCl2 carnallite and others.The large number of chloride contained in seawater.Also this element is a part of the chlorophyll of plants.
industrial chlorine is produced by electrolysis of sodium chloride, NaCl, melt or aqueous solution.And in fact, and in another case, the anode is allocated free chlorine Cl2 ↑.In the laboratory, a substance obtained by the action of concentrated hydrochloric acid to the potassium permanganate, KMnO4, manganese oxide (IV) MnO2, Berthollet salt KClO3 and other oxidants:

2KMnO4 + 16HCl = 2KCl + 2MnCl2 + 5Cl2 ↑ + 8H2O,

4HCl + MnO2 =MnCl2 + Cl2 ↑ + 2H2O,

KClO3 + 6HCl = KCl + 3Cl2 ↑ + 3H2O.

All of these reactions occur during heating.
Cl2 exhibits strong oxidizing properties in reactions with hydrogen, metals, some of the less electronegative nonmetal.Thus, the reaction with hydrogen takes place under the influence of rays of light in the dark is not:

Cl2 + H2 = 2HCl (hydrogen chloride).
When interacting with metal chlorides are obtained:

Cl2 + 2Na = 2NaCl (sodium chloride),

3Cl2 + 2Fe = 2FeCl3 (iron chloride (III)).
From less electronegative non-metals react with chlorine, can be called phosphorus and sulfur:

3Cl2 + 2P = 2PCl3 (chloride, phosphorus (III)),

Cl2 + S = SCl2 (chloridesulfur (II)).

with nitrogen and oxygen does not react directly with chloro.
chlorine reacts with water in two stages.First formed hydrochloric HCl and HClO hypochlorous acid, hypochlorous acid then decomposes into HCl and atomic oxygen:

1) Cl2 + H2O = HCl + HClO,

2) HClO = HCl + [O] (for the reaction light is needed).

resulting atomic oxygen causes oxidizing and bleaching action of chlorine water.It kills microorganisms and discolored organic dyes.
The reaction with acids chlorine does not enter.With alkali reacts differently, depending on the conditions.For cold formed chlorides and hypochlorites, when heated - chlorides and chlorates:

Cl2 + 2NaOH = NaClO + NaCl + H2O (cold),

6KOH + 3Cl2 = 5KCl KClO3 + + 3H2O (with heating).
bromide and metal iodide replaces chlorine free bromine and iodine:

Cl2 + 2KBr = 2KCl + Br2 ↓,

Cl2 + 2KI = 2KCl + I2 ↓.

fluoride similar reaction is not as oxidizing ability of fluoride higher oxidative capacity Cl2.