Abstract: The main elements of subgroup VII of the periodic table of elements Mendeleev

\nAll halogens argon very brutal. brainchild their vaporization causes botheration of the respiratory schema , and in cosmic quantities, they cause strangulation .\nEspeci wholey fluoride is poisonous : inhalation of down in the mouth quantities it causes pulmonary edema , large - the final stage of lung tissue death.\natomic number 17 is less deadly than fluoride. Chronic tipsiness by atomic number 17 causes discoloration of the face, lung and bronchial disease. As an antidote pair utilize alcohol and ether , and water vapor of ammonia.\nLiquid bromine in sense of touch with skin causes complete(a) burns. If skin mustiness wash organic bromine settlement ( benzene , CCl4), wiping with cotton wool soaked with this resoluteness .\n iodin is the to the lowest degree toxic of all the halogens. If skin lucid iodine leaves discolour stains . All jobs with halogens should be under the hood.\nalong with the halogens are resilient elements for human body. chlorine as NaCl person uses with food, it is a disclose of chlorophyll. pretermit of farad in imbibing water causes tooth decay. Iodine is involved in the regulation of metabolism. Lack of iodine causes the thyroid gland gland ( goitre ).\nExtraction of halogens.\nFluoride is obtained by passing an electric automobile current by dint of a fluoride dissolve (due to its large negativism ), such as CaF2, KHF2. Electrolysis is carried out in a nickel vessel , which is the cathode and the anode is carbon.\n chlorine is produced in industrial electrolysis of aqueous solutions of NaCl i KCl.