| Revision as of 15:09, 7 October 2002 view sourceDwmyers (talk | contribs)Extended confirmed users1,811 edits most of side bar complete. Need magnetism and electrical cond, if available.← Previous edit | Revision as of 19:01, 7 October 2002 view source Dwmyers (talk | contribs)Extended confirmed users1,811 edits splicing in original Hydrogen text.Next edit → | ||
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| == Notable Characteristics == | == Notable Characteristics == | ||
| Etymology: Greek ''hudôr'' (water) and ''gennen'' (generate). | Etymology: The name hydrogen, which comes from the French, in fact means ''water-maker'', ultimately from the Greek ''hudôr'' (water) and ''gennen'' (generate). | ||
| At ] conditions, hydrogen forms a ] ], H<font size="-1"><sub>2</sub></font>, with a boiling point of only 20.28 ] and a melting point of 13.81 K. Under exceedingly high pressures, like those found at the center of ]s, the molecules lose their identity and the hydrogen becomes a liquid ]. Under the exceedingly low pressure conditions found in space, hydrogen tends to exist as individual atoms, simply because there is no way for them to combine; clouds of H<font size="-1"><sub>2</sub></font> form and are associated with ]. | |||
| == Applications == | == Applications == | ||
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| == Occurrence == | == Occurrence == | ||
| Hydrogen is the most ] element in the universe, making up around 75% of normal matter. Hydrogen is the lightest chemical element; its atoms consist of a single ] and ]. The most common ] has no ]s, although there are two others - ] with one, and radioactive ] with two neutrons. | |||
| == Compounds == | == Compounds == | ||
| Hydrogen has an ] of 2.1, so it forms compounds where it is the more non-metallic and where it is the more metallic element. The former are called hydrides, where hydrogen either exists as H<font size="-1"><sup>-</sup></font> ions or just as a solute within the other element (as in ] hydride). The latter tend to be ], since the H<font size="-1"><sup>+</sup></font> ion would be a bare nucleus and so has a strong tendency to pull electrons to itself. Thus even in an ]ic solution one sees ions like H<font size="-1"><sub>3</sub></font>O<font size="-1"><sup>+</sup></font> as the protons latch on to something. | |||
| Hydrogen combines with oxygen to form ], H<font size="-1"><sub>2</sub></font>O, and releases a lot of energy in doing so, burning explosively in air. | |||
| == Isotopes == | == Isotopes == | ||
| Hydrogen has two stable isotopes: ] with one ] and no ]s (<font size="-1"><sup>1</sup></font>H) and ] with one proton and one neutron (<font size="-1"><sup>2</sup></font>H, D). Deuterium comprises 0.0184-0.0082% of all hydrogen (]); ratios of deuterium to protium are reported relative to the ] standard reference water. A radioactive isotope, ] (T or <font size="-1"><sup>3</sup></font>H) is another isotope and has one proton and two neutrons. | |||
| == Precautions == | == Precautions == | ||
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| *<br> | *<br> | ||
| *<br> | *<br> | ||
| ---- | |||
| See also:<br> | |||
| ], ], ], ]</font> | |||
Revision as of 19:01, 7 October 2002
This is a temporary page created for the sole purpose of converting the current Hydrogen article over to the new format agreed upon in Misplaced Pages talk:WikiProject Elements/Archive 1. When this process is complete the content in this page will be moved to the main article and any relevant edits made to that version will be incorporated into this version (this page will then be deleted from the database). For an example of what this article will look like when complete, please visit Beryllium, for a clean copy of the template used here please visit WikiProject Elements. See also periodic table to view the color scheme.
Hydrogen is a chemical element in the periodic table that has the symbol H and atomic number 1.
Notable Characteristics
Etymology: The name hydrogen, which comes from the French, in fact means water-maker, ultimately from the Greek hudôr (water) and gennen (generate).
At standard temperature and pressure conditions, hydrogen forms a diatomic gas, H2, with a boiling point of only 20.28 K and a melting point of 13.81 K. Under exceedingly high pressures, like those found at the center of gas giants, the molecules lose their identity and the hydrogen becomes a liquid metal. Under the exceedingly low pressure conditions found in space, hydrogen tends to exist as individual atoms, simply because there is no way for them to combine; clouds of H2 form and are associated with star formation.
Applications
History
Occurrence
Hydrogen is the most abundant element in the universe, making up around 75% of normal matter. Hydrogen is the lightest chemical element; its atoms consist of a single proton and electron. The most common isotope has no neutrons, although there are two others - deuterium with one, and radioactive tritium with two neutrons.
Compounds
Hydrogen has an electronegativity of 2.1, so it forms compounds where it is the more non-metallic and where it is the more metallic element. The former are called hydrides, where hydrogen either exists as H ions or just as a solute within the other element (as in Palladium hydride). The latter tend to be covalent, since the H ion would be a bare nucleus and so has a strong tendency to pull electrons to itself. Thus even in an acidic solution one sees ions like H3O as the protons latch on to something.
Hydrogen combines with oxygen to form water, H2O, and releases a lot of energy in doing so, burning explosively in air.
Isotopes
Hydrogen has two stable isotopes: protium with one proton and no neutrons (H) and deuterium with one proton and one neutron (H, D). Deuterium comprises 0.0184-0.0082% of all hydrogen (IUPAC); ratios of deuterium to protium are reported relative to the VSMOW standard reference water. A radioactive isotope, tritium (T or H) is another isotope and has one proton and two neutrons.
Precautions
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External Links
External links used only for conversion (please delete before pasting into main article)
See also:
Periodic Table, hydrogen bond, hydrogen atom, Antihydrogen