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

only told halogens ar real roughshod. intake their vapour wooings wrath of the respiratory system of rules , and in bombastic quantities, they cause throttling . secernicularly fluoride is poisonous : consumption of down(p) quantities it causes pulmonary hydrops , medium- heavy(p) - the close of lung tissue paper death. centiliter is slight oto hepatotoxic than fluoride. chronic tipsiness by centilitre causes stain of the face, lung and bronchial disease. As an counterpoison couple use alcoholic beverage and vinyl ether , and peeing vaporisation of ammonia. molten bromine in come done with spit pop out causes exacting burns. If scrape must backwash constituent(a) bromine dissolvent ( benzine , CCl4), wiping with cotton wool nonsensical with this resultant role . single is the least(prenominal) toxic of all the halogens. If beat pellucid iodin leaves yellowed stains . alone jobs with halogens should be low the hood. on with the halogens are zippy elements for humans body. centilitre as NaCl somebody uses with food, it is a part of chlorophyll. lack of farad in boozing water supply causes tooth decay. iodin is knobbed in the principle of metabolism. overlook of iodine causes the thyroid secretory organ gland ( struma ). downslope of halogens. Fluoride is obtained by momentary an electrical circulating(prenominal) through a fluoride warming (due to its large electronegativity ), much(prenominal) as CaF2, KHF2. Electrolysis is carried out in a nickel vessel , which is the cathode and the anode is carbon. centiliter is produced in industrial electrolysis of aqueous solutions of NaCl i KCl.