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Difference between revisions of "Oxygen"

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(Chemical Properties)
 
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{{Element | name=Oxygen | symbol=O | anumber=8 | amass=16.0 amu | state=gas | class=Non-metal | cstructure=Cubic | color=Colorless | date=1774 | discname=[[Joseph Priestley]] | origname=From the Greek words ''oxus'' (acid) and ''gennan'' (generate) | uses=Supports life | obtained=From liquid air}}
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{{Element | name=Oxygen | symbol=O | anumber=8 | amass=15.994 amu | state=gas | class=Non-metal | cstructure=Cubic | color=Colorless | date=1774 | discname=[[Joseph Priestley]] | origname=From the Greek words ''oxus'' (acid) and ''gennan'' (generate) | uses=Supports life | obtained=From liquid air}}
'''Oxygen''' is a [[chemical]] [[element]] with 8 [[proton]]s.<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref> Oxygen's [[atomic mass]] is slightly under 16, since it also has 8 [[neutron]]s (a slight amount of mass is "lost" in the energy contained in the [[subatomic bond]]s).
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'''Oxygen''' is the third most abundant element in the universe by mass and is essential to life on Earth.
  
The name "oxygen" means "acid maker": Many common acids -- nitric, sulfuric, phosphoric, etc. -- are just hydrogen nitrate, hydrogen sulfate, or hydrogen phosphate, where the nitrate, sulfate, and phosphate complexes involve oxygen.
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==Chemical Properties==
  
Under normal conditions oxygen is a colorless, odorless [[gas]] consisting of two oxygen [[atom|atoms]] which has the chemical formula O<sub>2</sub>. This means it is [[diatom]]ic.  Approximately 20% of the [[atmosphere]] is made up of oxygen.  Oxygen also forms a [[triatomic]] molecule called [[ozone]] (O<sub>3</sub>), which, although unstable under normal conditions, is a very important ingredient in the upper [[atmosphere]], forming a layer which blocks most of the [[Sun]]'s [[ultraviolet]] radiation.
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At normal [[atmospheric pressure]] oxygen melts at 54.36 [[Kelvin]] (K) and boils at 90.2 K; on Earth it essentially exists only as a gas. It readily dissolves in water, which makes aquatic life possible. Under normal conditions oxygen forms molecules consisting of two oxygen atoms each sharing two electrons in the 2p subshell; this form of oxygen is known as O<sub>2</sub>. O<sub>2</sub> is a colorless, odourless gas. In liquid form (below -193 degrees Celsius) it is pale blue.
  
Oxygen is highly reactive, and in many other elements and compounds undergo [[exothermic reaction]]s with it (they [[combustion|burn]] or [[oxidation|rust]]).  If it were not for its continual replenishment as a waste product of plant [[photosynthesis]], all atmospheric oxygen would disappear, forming compounds with other chemicals at the earth's surface.
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==Isotopes==
  
Many [[animal]]s depend upon oxygen as a highly efficient ingredient for breaking down [[food]] for [[energy]], due to its reactivity.  Those that do not are called "[[anaerobic]]", meaning "without air", and include many important [[bacteria]].  
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There are three stable and 14 radioactive isotopes of oxygen. The stable isotopes are <sup>16</sup>O, <sup>17</sup>O and <sup>18</sup>O, with <sup>16</sup>O being by far the most common. Radioisotopes range from <sup>10</sup>O to <sup>26</sup>O, with the two most stable being <sup>15</sup>O and <sup>14</sup>O. This gives oxygen an atomic weight of slightly below 16.<ref>http://education.jlab.org/itselemental/iso008.html</ref>
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==Compounds==
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Oxygen is highly reactive. It reacts readily with most metals and many other elements, either through combustion or oxidation. As a result, many naturally occurring compounds contain oxygen.
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==Occurrence in Nature==
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Oxygen is the third most abundant element in the universe by mass after [[hydrogen]] and [[helium]]; approximately 5.9% of the mass of our [[solar system]] consists of oxygen. However, due to the large disparity in atomic weight between all isotopes of oxygen compared with <sup>1</sup>H and <sup>4</sup>He, less than 0.5% of the atoms in the solar system are oxygen atoms.{{fact}}
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Due to its reactivity free oxygen is extremely rare in nature and would not exist on Earth without the process of [[photosynthesis]]. Geologists and paleontologists believe that free oxygen first appeared during the "Great Oxygenation Event" around 2.4 billion years ago. Young-Earth creationists reject this timescale.
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{{Periodic table}}
  
 
==References==
 
==References==
<references/>
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{{Reflist}}

Latest revision as of 23:00, November 5, 2016

Oxygen
Properties
Atomic symbol O
Atomic number 8
Classification Non-metal
Atomic mass 15.994 amu
Other Information
Date of discovery 1774
Name of discoverer Joseph Priestley
Name origin From the Greek words oxus (acid) and gennan (generate)
Uses Supports life
Obtained from From liquid air

Oxygen is the third most abundant element in the universe by mass and is essential to life on Earth.

Chemical Properties

At normal atmospheric pressure oxygen melts at 54.36 Kelvin (K) and boils at 90.2 K; on Earth it essentially exists only as a gas. It readily dissolves in water, which makes aquatic life possible. Under normal conditions oxygen forms molecules consisting of two oxygen atoms each sharing two electrons in the 2p subshell; this form of oxygen is known as O2. O2 is a colorless, odourless gas. In liquid form (below -193 degrees Celsius) it is pale blue.

Isotopes

There are three stable and 14 radioactive isotopes of oxygen. The stable isotopes are 16O, 17O and 18O, with 16O being by far the most common. Radioisotopes range from 10O to 26O, with the two most stable being 15O and 14O. This gives oxygen an atomic weight of slightly below 16.[1]

Compounds

Oxygen is highly reactive. It reacts readily with most metals and many other elements, either through combustion or oxidation. As a result, many naturally occurring compounds contain oxygen.

Occurrence in Nature

Oxygen is the third most abundant element in the universe by mass after hydrogen and helium; approximately 5.9% of the mass of our solar system consists of oxygen. However, due to the large disparity in atomic weight between all isotopes of oxygen compared with 1H and 4He, less than 0.5% of the atoms in the solar system are oxygen atoms.[Citation Needed]

Due to its reactivity free oxygen is extremely rare in nature and would not exist on Earth without the process of photosynthesis. Geologists and paleontologists believe that free oxygen first appeared during the "Great Oxygenation Event" around 2.4 billion years ago. Young-Earth creationists reject this timescale.

References