Basic information Atomic Number: 7 Atomic Radius: 71 pm Atomic Symbol: N Melting Point: -210.0 °C Atomic Weight: 14.00674 Boiling Point: -195.79 °C Electron Configuration: [He]2s22p3 Oxidation States: -3,5 Discoverer: Daniel Rutherford Discovered at: Scotland Discovery date: 1772 Origin of name: From the Greek words "nitron genes" meaning "nitre" and "forming" and the Latin word "nitrum" (nitre is a common name for potassium nitrate, KNO#) Nitrogen - chemical elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78% by volume of Earth's atmosphere. Discovery of Nitrogen It was known during the 18th century that air contains at least two gases, one of which supports combustion and life, and the other of which does not. Nitrogen was discovered by Daniel Rutherford in 1772, who called it noxious air, but Scheele, Cavendish, Priestley, and others at about the same time studied "burnt" or "dephlogisticated" air, as air without oxygen was then called. Rutherford discovered "noxious air" by putting a mouse inside of a bell jar and waited for him to suffocate. When the mouse suffocated he put another mouse in the jar that died a short time later. Nitrogen is a Noble Gas which makes it for the most part inert unless subjected to catalysts or high temperatures and or pressures. The element seemed so inert that Lavoisier named it azote, meaning "without life". Properties Nitrogen is a nonmetal, with an electronegativity of 3.04. It has five electrons in its outer shell and is therefore trivalent in most compounds. The triple bond in molecular nitrogen (N2) is the strongest in nature. The resulting difficulty of converting N2 into other compounds, and the ease (and associated high energy release) of converting nitrogen compounds into elemental N2, have dominated the role of nitrogen in both nature and human economic activities. At atmospheric pressure molecular nitrogen condenses (liquifies) at −195.8 °C and freezes at 63 K −210.0 °C into the beta hexagonal close-packed crystal allotropic form. Below 237.6 °C nitrogen assumes the alpha cubic crystal allotropic form. Liquid nitrogen, a fluid resembling water in appearance, but with 80.8% of the density (the density of liquid nitrogen at its boiling point is 0.808 g/mL), is a common cryogen. Unstable allotropes of nitrogen consisting of more than two nitrogen atoms have been produced in the laboratory, like N3 and N4. Under extremely high pressures (1.1 million atm) and high temperatures (2000 K), as produced using a diamond anvil cell, nitrogen polymerizes into the single-bonded cubic gauche crystal structure. This structure is similar to that diamond, and both have extremely strong covalent bonds. N4 is nicknamed "nitrogen diamond." Uses of Nitrogen Uses as inert gas Nitrogen gas (N2) is often used as a replacement for air where oxidation is undesirable. One area for use is to preserve the freshness of foods by packaging them in nitrogen. This greatly reduces the spoilage of the food, due to it getting rancid or suffering other forms of oxidative damage. For years, argon gas had been used in incandescent light bulbs to prevent the tungsten filament from burning up, since argon is an inert material. Nitrogen is now being used as an inexpensive alternative to argon. Other areas where nitrogen is used is in dealing with liquid explosives as a safety measure, in military aircraft fuel systems to reduce the fire hazard, and in the production of electronic parts such as transistors, diodes and integrated circuits. Uses of nitrogen in form of amonia The most important use of nitrogen is in making ammonia (NH3), which is a colorless gas with a strong odor, similar to the smell of urine. The reason is because urine contains some ammonia. Fertilizer A major use of ammonia is in making fertilizers. Ammonia can be used directly as fertilizer by adding it to irrigation water for plants that needing much nitrogen. It is also used to produce the urea (NH2CONH2), which is used as a fertilizer. Another important use of ammonia is to create nitric acid (HNO3), which is then also used to make fertilizer. Other uses Many people use household ammonia as a disinfectant. Nitric acid—made form ammonia—is used in explosives. Ammonia is also used in the plastic industry and as a feed supplement for livestock. A further example of its versatility is its use as a preferred alternative to carbon dioxide to pressurize kegs of some beers, particularly stouts and British ales, due to the smaller bubbles it produces, which make the dispensed beer smoother and headier. A modern application of a pressure sensitive nitrogen capsule known commonly as a "widget" now allows nitrogen charged beers to be packaged in cans and bottles. Liquid nitrogen Nitrogen is a liquid at temperatures below −196.5 °C and is used as a refrigerant for such things as preservation of blood and cooling of large computer systems, as well as some industrial uses. Being a liquid, it is more convenient to use for low temperature cooling than dry ice. Liquid nitrogen is also used in oil wells to build up pressure in order to force crude oil upward. Sources: http://en.wikipedia.org/wiki/Nitrogen http://periodic.lanl.gov/elements/7.html http://www.webelements.com/nitrogen/ http://web1.caryacademy.org/chemistry/rushin/StudentProjects/ElementWebSites/nitrogen/history.htm