Arsenic is a chemical element which in periodic Mendeleev's system is in the fifth group under atomic number 33, represents gray and steel crystals.
Instruction
1. The Latin name of arsenic - Arsenicum - comes from the Greek word arsen that means strong, courageous. Such name is probable it is given an element thanks to its strong influence on a human body.
2. Physical properties the myshyakadanny element can be presented by several allotropic modifications, the steadiest of which is gray (metal) arsenic. It is presented by the fragile metal weight having characteristic metal gloss on a fresh break and which is quickly growing dull in damp air. With an atmospheric pressure and temperature of 615 degrees steam of arsenic (there is a sublimation), which when cooling a surface with liquid air is condensed is formed and forms yellow arsenic. This modification is presented soft as wax, transparent crystals which at influence of light and small heating is passed into gray arsenic again. Brown and black modifications of an element are also known (steklovido-amorphous). At sedimentation of vapors of arsenic on glass there is a formation of a mirror film. Though arsenic more is nonmetal, its conductivity at temperature increase decreases, as at any typical metal.
3. Chemical properties myshyakamyshyak is an acid-forming element, but salts, for example, with sulfuric acid it does not create therefore it is considered often semi-metal. In an initial look this element rather inert, on it the water, alkalis and acids which do not have oxidizing properties do not make any impact. At reaction with the diluted nitric acid it is oxidized with formation of orthoarsenous acid, and with concentrated gives orthoarsenical acid. In interaction of arsenic and active metals arsenides (soleobrazny connections) which are subject to hydrolysis by water are formed. In acidic environment this reaction goes especially quickly and is formed arsin - it is very poisonous gas which in itself has no color and a smell, but at the expense of the content of impurity the garlic smell appears. Decomposition of an arsin on elements begins already at the room temperature and sharply accelerates when heating. At sublimation of couple of arsenic on air quickly burn down a blue flame, heavy white vapors of arsenous anhydride which is the most widespread myshyaksoderzhashchy reagent are as a result formed.