Chalcogens


 * ** Element ** || ** Symbol ** || ** Appearance ** || ** Atomic Number ** || ** Atomic Mass ** || ** Number of proton's ** || ** Number of valence electron/s ** || ** Number of shells ** || ** Melting point ** || ** Boiling point ** || ** Atomic Radius ** || ** Discovery Date ** || ** Density at **** 293 K **  || ** Physical state at room temperature and pressure ** ||
 * ** Oxygen ** ||  O  || The gas is colourless, odourless and tasteless. The liquid and solid forms are a pale blue colour and are strongly paramagnetic. ||  8  ||  15.9994 amu  ||  8  ||  6  ||  2  ||  -218.79 °C  ||  -182.95 °C  ||  66 pm  || Oxygen was first discovered by Swedish pharmacist Carl Wilhelm Scheele, in 1774. ||  0.001429 g/cm3  ||  Gas  ||
 * ** Sulfur ** || S  || Sulfur is pale yellow, odourless, brittle solid, which is insoluble in water. ||  16  ||  32.065 amu  ||  16  ||  6  ||  3  ||  119.6 °C  ||  444.60 °C  ||  104 pm  || Sulfur was known in the ancient times and has no exact date found. ||  2.07 g/cm3  ||  Solid  ||
 * ** Selenium ** || Se  || Selenium exists in several allotropic forms, although three are generally recognized. Selenium can be prepared with either an amorphous or a crystalline structure. The colour of amorphous selenium is either red, in powder form, or black, in vitreous form. Crystalline monoclinic selenium is a deep red; crystalline hexagonal selenium, the most stable variety, is a metallic gray. ||  34  ||  78.96 amu  ||  34  ||  6  ||  4  ||  220.5 °C  ||  685 °C  ||  117 pm  || Selenium was discovered in 1817 by Jöns Jakob Berzelius. ||  4.79 g/cm3  ||  Solid  ||
 * ** Tellurium ** || Te  || Crystalline tellurium has a silvery-white appearance, and when pure it exhibits a metallic luster. It is brittle and easily pulverized. ||  52  ||  127.60 amu  ||  52  ||  6  ||  5  ||  449.5 °C  ||  988 °C  ||  143.2 pm  || Tellurium was discovered in 1782 by Franz-Joseph Müller von Reichenstein. ||  6.24 g/cm3  ||  Solid  ||
 * ** Polonium ** || Po  || Polonium is a rare, silvery-gray, radioactive low-melting metalloid. ||  84  ||  209 amu  ||  84  ||  6  ||  6  ||  254 °C  ||  962 °C  ||  167 pm  || Polonium was discovered in 1898 by Marie Skłodowska-Curie and Pierre Curie, in France. ||  9.4 g/cm3  ||  Solid  ||

- The atomic numbers and the numbers of protons in each element have a trend, as they increase between each element. - The atomic mass, the atomic radius and the number of shell for each element are also increasing numbers. - The number of valance electrons for each element are all 6. - Both the melting point and the boiling points of the elements begin to increase from oxygen and then drop once they reach Polonium. The melting point drops quite dramatically but the boiling point just slightly drops. - The Chalcogen group consists of elements that are non-metals, metalloids and post transition metals. The elements oxygen and sulfur are non-metals, while selenium and tellurium are metalloids and lastly, polonium which is a post transition metal. - The physical state at room temperature of all the Chalcogen elements is solid except for oxygen which is gas.
 * Trends: **

** Oxygen Uses: ** The major commercial use of oxygen is in steel production, rocket propellant and in plastics and textiles. Plants and animals rely on oxygen for respiration. Oxygen is frequently used to help breathing in patients with respiratory ailments. ** Sulfur Uses: ** Sulfur's main commercial use is as a reactant in the production of sulfuric acid (H2SO4). Sulfuric acid is the industrialized world's number one bulk chemical, required in large quantities in lead-acid batteries for automotive use. Sulfur is also used in the vulcanization of natural rubber, as a fungicide, in black gunpowder, in detergents and in the manufacture of phosphate fertilizers. ** Selenium Uses: ** Selenium is used in Xerography for reproducing and copying documents, letters, etc. It is used by the glass industry to decolorize glass and to make ruby-coloured glasses and enamels. It is also used as a photographic toner, and as an additive to stainless steel. ** Tellurium Uses: ** Tellurium is alloyed with copper and stainless steel to make these metals more workable. It is added to lead to decreases the corrosive action of sulfuric acid and to improve its strength and hardness. Tellurium is used as a colouring agent in ceramics. Tellurium is also used in the electronic industry. It is used in vulcanizing rubber and in catalysts for petroleum cracking and in blasting caps for explosives. == ** Polonium Uses: ** Polonium is used to eliminate static electricity produced during processes such as rolling paper, wire and sheet metal. However, beta decay sources are more commonly used as they are less dangerous. Polonium also can be used as an atomic heat source but because of the isotope's short half-life, it doesn't provide power for long-term uses. Polonium is also used in anti-static brushes to eliminate dust on photographic film. It is sealed in brushes to control the radioactive emissions. == Chemical Compounds that are produced or created by the elements of the Chalcogen group are known as Chalcogenides. Although all group 16 elements of the periodic table are defined as a Chalcogen, the term is more commonly reserved for sulfides, selenides, and tellurides, rather than oxides.
 * Uses: **
 * Compounds: **
 * Oxygen ** : As oxygen is a highly active metal, it can form chemical bonds with almost all other elements at elevated temperatures to give corresponding oxides, but the most common compound that oxygen is known for is H2O or most commonly known as water. Hydrogen and oxygen bond together to produce the chemical, H2O.
 * Sulfur: ** Sulfur bonded with hydrogen produces the chemical SO2, hydrogen sulfide. Sulfur can also form stable compounds with almost any elements apart from noble gases.
 * Selenium ** : Selenium forms SeO2, known as Selenium dioxide. Selenium dioxide is formed by the reaction of elemental selenium with oxygen.
 * Tellurium: ** **Tellurium forms the compound Zinc Telluride, by heating the combination of tellurium and zinc. **
 * Polonium: ** **Polonium cannot form common compounds; they can only be synthetically created. **

**__ Bibliography __** [] 5th of November, 2010. [] 5th of November, 2010. [] 5th of November, 2010. [] 5th of November, 2010.
 * __ Oxygen: __**
 * Oxygen Image: **

[] 5th of November, 2010 [] 5th of November, 2010. [] 5th of November, 2010. [] 5th of November, 2010
 * __ Tellurium: __**
 * Tellurium Image: **

[] 6th of November, 2010 [] 6th of November, 2010. [] 6th of November, 2010. [] 6th of November, 2010 [] 6th of November, 2010. [] 6th of November, 2010. [] 6th of November, 2010. [] 6th of November, 2010. [] 6th of November, 2010. [] 6th of November, 2010
 * __ Selenium: __**
 * Selenium Image: **
 * __ Sulfur: __**
 * Sulfur Image: **

[] 7th of November, 2010 [] 7th of November, 2010. [] 7th of November, 2010. [] 7th of November, 2010. [] 7th of November, 2010. [] 7th of November, 2010. [] 7th of November, 2010 [] 5th of November, 2010. 6th of November, 2010. 7th of November, 2010.
 * __ Polonium: __**
 * Polonium Image: **
 * __ All elements: __**