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Atomic symbol: K |
Atomic number: 19 |
Atomic weight: 39.0983 |
Atomic volume: 45.46 cm3/mol |
Density: 0.862 g/cm3 |
Period Number: 4 |
Group number: 1 |
Group name: Alkali Met. |
Element classification: Metal |
Phase at room temperature: Solid |
Melting Point: 336.5 K |
Boiling point: 1038.7 K |
Heat of fusion: 2.334 kJ/mol |
Heat of vaporization: 79.870 kJ/mol |
Ionization Energy: 4.341 eV |
1st ionization energy: 418.8 kJ/mole |
2nd ionization energy: 3051.3 kJ/mole |
3rd ionization energy: 4411.3 kJ/mole |
Electronegativity: 0.82 |
Electron affinity: 48.385 kJ/mole |
Specific heat: 48.385 kJ/mole |
Heat atomization: 90 kJ/mole atoms |
Shells: 2,8,8,1 |
Electron Shell Configuration: [Ar] 4s1 |
Minimum oxidation number: 0 |
Maximum oxidation number: 1 |
Minimum common oxidation number: 0 |
Maximum common oxidation no: 1 |
Appearance & Characteristics |
Structure:: bcc: body-centered cubic |
Color: silvery-white |
Hardness: 0.5 mohs |
Toxicity: ? |
Characteristics: soft |
Uses: fertilizer, low-Na salt |
Reaction with air: vigorous, =>KO2 |
Reaction with 6M HCl: vigorous, =>H2, KCl |
Reaction with 15M HNO3: vigorous, =>H2, NOx, KNO3 |
Reaction with 6M NaOH: vigorous, =>H2, KOH |
Number of isotopes: 3 |
Oxide(s): K2O |
Hydride(s): KH |
Chloride(s): KCl |
Atomic Radius: 227 pm |
Ionic radius (1- ion): pm |
Ionic radius (1+ ion): 152 pm |
Ionic radius (2- ion): pm |
Ionic radius (2+ ion): pm |
Ionic radius (3+ ion): pm |
Thermal conductivity: 102.5 J/m-sec-deg |
Electrical conductivity: 138.9 1/mohm-cm |
Polarizability: 43.4 A^3 |
Source: Sylvite, carnallite (misc) |
Relative abundance solar system: 3.576 log |
Abundance earth's crust: 4.3 log |
Estimated crustal abundance: 2.09×104 milligrams per kilogram |
Estimated oceanic abundance: 3.99×102 milligrams per liter |
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(English, potash - pot ashes; L.. kalium, Arab qali: alkali) Discovered in 1807 by Davy, who obtained it from caustic potash (KOH); this was the first metal isolated by electrolysis. |
The metal is the seventh most abundant and makes up about 2.4% by weight of the earth's crust. Most potassium minerals are insoluble and the metal is obtained from them only with great difficulty.
Certain minerals, however, such as sylvite, carnallite, langbeinite, and polyhalite are found in ancient lake and sea beds and form rather extensive deposits from which potassium and its salts can readily be obtained. Potash is mined in Germany, New Mexico, California, Utah, and elsewhere. Large deposits of potash, found at a depth of some 3000 ft in Saskatchewan, promise to be important in coming years.
Potassium is also found in the ocean, but is present only in relatively small amounts, compared to sodium.
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It is one of the most reactive and electropositive of metals. Except for lithium, it is the lightest known metal. It is soft, easily cut with a knife, and is silvery in appearance immediately after a fresh surface is exposed. It rapidly oxidizes in air and must be preserved in a mineral oil such as kerosene.
As with other metals of the alkali group, it decomposes in water with the evolution of hydrogen. It catches fire spontaneously on water. Potassium and its salts impart a violet color to flames.
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The greatest demand for potash has been in its use for fertilizers. Potassium is an essential constituent for plant growth and is found in most soils.
An alloy of sodium and potassium (NaK) is used as a heat-transfer medium. Many potassium salts are of utmost importance, including the hydroxide, nitrate, carbonate, chloride, chlorate, bromide, iodide, cyanide, sulfate, chromate, and dichromate.
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Seventeen isotopes of potassium are known. Ordinary potassium is composed of three isotopes, one of which is 400K (0.0118%), a radioactive isotope with a half-life of 1.28 x 109 years. |
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SEKOM Handelsges.m.b.H.... |
Our company is a private firm founded in 1990 with aim to develop export and import with Russia. We do promote EU industrial and consumer goods in Russia and strongly support marketing of Russian and CIS industrial products and services.
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