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Gaffer Variety:
Elements 13 SN2 015:
By Willie Gaffer:
Argon:
Argon, symbol Ar, is a colorless, odorless, inert gaseous element constituting approximately one percent of Earth's atmosphere, from which it is commercially obtained by fractionation for use in electric light bulbs, fluorescent tubes, and radio vacuum tubes. It is also used as an inert gas shield in arc welding. The atomic number is 18, the atomic weight is 39.94, the melting point is -189.2°C, and the boiling point is -185.7°C. The electron configuration is 2, 8, and 8, hence te valence is 0. Argonn group 8A of the periodic table making it one of the noble gases. The atoms do not combine with each other, or with any other element.
Argon is the most abundant and most frequently used of the noble gases. It was first isolated in 1894 by the British scientists Lord Rayleigh and Sir William Ramsay. Rayleigh was a British physicist and Ramsay was a chemist. This was back in the days when members of royalty were making contributions to human progress rather than freeloading off the peasant class as they do now.
They realized that nitrogen made by removing oxygen from air is about 0.5 percent more dense than nitrogen derived from other chemical sources such as ammonia and they understood the significance of that. There was another heavier gas that remained after oxygen and nitrogen were removed.
A major portion of earths argon was produced, since the Earth's formation. It turns out that argon-40 is created when the radioactive potassium-40 decays. Once formed, argon leaks into the atmosphere from the rocks. This process is ongoing. This decay gives one method of determining the age of our earth. The technique is called potassium-argon dating. There are three stable isotopes of argon, those being argon-36, argon-38, and argon-40.
Potassium:
Potassium, Symbol K, is a soft, silver-white, highly reactive metallic element. It is so reactive that in nature we only find it in compounds. The atomic number is 19, the atomic weight is 39.102, the melting point is 63.65°C, the boiling point 774°C, and the specific gravity is 0.862. Potassium is in group 1A, giving it a valence of 1. The electron shell configurations are 2, 8, 8, 1.
Potassium exists in three natural isotopic forms, with mass numbers 39, 40, and 41. Potassium-40 is radioactive and has a half-life of 1.28 billion years. This, as we learned above is the major source of argon-40. The most abundant isotope is potassium-39. Potassium is plentiful on earth found in combination with other elements. It I a necessary constituent of all animal and plant life. It is one of the essential three fertilizers used in agriculture. The other two being nitrogen and phosphorous.
The metal is generated in the electrolysis of fused potassium hydroxide or of a mixture of potassium chloride and potassium fluoride. The metal oxidizes as soon as it is exposed to air and it reacts violently with water, producing potassium hydroxide and hydrogen gas. When this happens, the hydrogen gas burns rather violently. Hence potassium cannot be exposed to water after it is created. It is usually stored in some kind of liquid that will not react with it.
Potassium forms many compounds which closely resemble compounds of sodium. Here are some of the most important ones. Potassium bromide (KBr), a white solid formed by the reaction of potassium hydroxide and bromine, is used in photography, engraving, and lithography, and in medicine as a sedative. Potassium chromate (K2CrO4), a yellow crystalline solid, and potassium bichromate, or potassium dichromate (K2 Cr2O7), a red crystalline solid, are powerful oxidizing agents used in matches and fireworks, in textile dyeing, and in leather tanning. Potassium iodide (KI), a white crystalline compound that is very soluble in water, is used in photography for preparing gelatin emulsions and in medicine. Potassium nitrate (KNO3), is a white solid used in matches, explosives, and fireworks among other things. This one occurs naturally as saltpeter. Potassium permanganate (KMnO4), a purple crystalline solid, is used as a disinfectant and germicide and as an oxidizing agent in many important chemical reactions. Potassium sulfate (K2SO4), is a white crystalline solid. This may be the most important form of the element as potassium fertilizer.
Potassium is also important in the manufacture of soaps. In
that form it is called potash. It was
originally obtained by the leaching of wood ashes. Remember your
American history books where the making of soap was
extravagantly romanticized. In that process
soap was produced from waste fat and lye. Lye is a very strong alkali made from
leaching wood ashes. In spite of your history books, this process was done long before a pilgrim ever set foot in the
Calcium:
Calcium, Symbol Ca, is a silvery, moderately hard metallic element that constitutes approximately 3 percent of the earth's crust and is a basic component of most animals and plants. It occurs naturally in limestone, gypsum, and fluorite, and its compounds are used to make plaster, quicklime, Portland cement, and metallurgic and electronic materials. The atomic number is 20. the atomic weight is 40.08, the melting point is 842 to 848°C, the boiling point is 1,487°C, and the specific gravity 1.55. It is found in group 2A with an electron shell configuration of 2, 8, 8, 2 giving it a valence of 2.
Calcium has six stable and several radioactive isotopes. It is fifth in abundance among the elements in the earth's crust, but it is not found uncombined in nature. It occurs in many highly useful compounds, such as calcium carbonate, calcium sulfate, and calcium phosphate. It also occurs in many silicates. When heated it unites with the halogens, oxygen, sulfur, phosphorus, hydrogen, and nitrogen. It reacts violently with water, forming the hydroxide Ca(OH)2 while releasing hydrogen.
Calcium is normally produced by electrolysis of fused calcium chloride, which is a costly process. It is used as a deoxidizer for copper, nickel, and stainless steel. An alloy of calcium and lead is harder than making it preferable for lead acid battery grids, bearings, and sheathing for cable. Calcium is found in lime, cement and mortar, teeth and bones, and in many body fluids. It is essential to animal muscle function, nerve impulses, and the blood clotting.