The plastic metal
Before find out which element from the periodic table has the title of «most plastic metal», you need to clearly understand what is plasticity. This is one of the physical properties associated with the structure of the metal.
Plasticity is the ability to take a new form, without causing the rupture of ionic bonds. In practice, the result of plasticity there is a good ductility, so that the metals can be used in industry, medicine, electrical engineering and agriculture. Of the 126 elements in the periodic table, gold is recognized as the most ductile metal. With today’s technology it can be pulled into a thin thread that will not be noticeable to the human eye.
Why specialists in the manufacture and repair of jewelry put gold in the first place? First and foremost, this is due to the excellent plasticity: from 1 gram of the metal can be stretched into a wire up to 3 kilometers, gold bars prokovyvayut in sheets whose thickness is measured in thousandths of a millimeter. This gold-covered domes of churches, it is called foil. In appearance it is quite interesting: the gap gives a blue-green tint.
Pure gold is soluble in Aqua Regia. So-called mixture of the two concentrated acids: nitric and hydrochloric. The plastic metal in the table is at number 79, melting point – 1064 °C, density is for 19.32 g/cm3. The thermal conductivity and electrical resistance of gold, second only to silver and copper.
Gold in its pure form is very soft, so jewelry made, usually, of the alloys. Most of the gold add silver or copper. Thought earlier, that means «test» on the jewelry? This is the content of gold in its pure form in thousandths. 999 is considered pure gold.
Gold has long been used as an investment object, in addition it has found extensive use in the jewelry industry.
In many countries gold coins were used as money. Despite this as the world currency it is recognized only in the 19th century. In 1922 in Russia appeared in circulation banknotes with gold content, which are called «coins». One ticket was equivalent to 10 gold rubles old coinage.
Gold is the most common material used in the manufacture of jewelry. The higher the gold alloy, the better corrosion resistance will have the material, durability and the different color shades lend silver and copper.