Davy, Humphry calcium

Calcium was named by Humphry Davy after the material from which it was produced, calx, the Latin for limestone. Davy isolated calcium metal in 1808 by electrolysis. Although calcium never occurs in elemental form, calcium compounds are widely found in nature, particularly in limestone and gypsum. Calcium metal is used in the production and purification of other metals, while calcium compounds have thousands of uses, including chemical production, plaster, and Portland cement. 

There are four stable isotopes of strontium that are found naturally. In addition there are about twenty radioactive isotopes, including strontium-90, a deadly by-product of nuclear-bomb detonations. The natural forms of strontium are relatively nontoxic. Similar to calcium both physically and chemically, elemental strontium is a soft, shiny metal. Like calcium and other alkaline earth metals, it is easily oxidized and thus not found naturally in its free elemental state. Instead, it almost always is found in the + 2 oxidation state, forming such compounds as strontium oxide (SrO), strontium sulfate (SrS04, from the mineral celestite), strontium carbonate (SrCOj, from the mineral strontianite), and strontium chloride (SrC. Strontium nitrate, Sr(N03)2, is used to produce the brilliant red color seen in some fireworks and signal flares and is also used in making tracer bullets that can be seen when fired at night. Other strontium compounds are sometimes used in the manufacture of special glasses. Yet overall, strontium is not a very important element industrially or commercially, see ALSO Davy, Humphry... 

Calcium was first isolated by Sir Humphry Davy in 1808. Davy produced calcium amalgam by electrolyzing an aqueous solution of the chloride, CaCl, using a liquid-mercury cathode such as in the chlor-alkali process employing a mercury cathode. After distilling mercury from the amalgam formed, he obtained the pure calcium metal. His discovery showed lime to be an oxide of calcium. Later, Moissan reduced the calcium diiodide with sodium. The first industrial production of calcium metal was reported in 1904 and attributed to Brochers and Stockem, who prepared it by electrolysis of the molten chloride. This process was discontinued in 1940 and replaced by aluminothermic reduction of the oxide. 

Calcium - the atomic mmiber is 20 and the chemical symbol is Ca. The name derives from the Latin calx for lime (CaO) or limestone (CaCOj) in which it was foimd. It was first isolated by the British chemist Humphry Davy in 1808 with help from the Swedish chemist Jons Jacob Berzelius and the Swedish court physician M.M. af Pontin, who had prepared calcimn amalgam. 

In 1807 Sir Humphry Davy (1778-1829) devised an electrolysis apparatus that used electrodes immersed in a bath of melted sodium hydroxide. When he passed an electric current through the system, metallic sodium formed at the negative (cathode) electrode. He first performed this experiment with molten potassium carbonate to liberate the metal potassium, and he soon followed up with the sodium experiment. Today, sodium and some of the other alkali metals are still produced by electrolysis. The types of electrolytes may vary using a mixture of sodium chloride and calcium chloride and then further purifying the sodium metal. 

By the early 1800s several chemists had separated potassium and sodium as elements from compounds. It was believed that metallic calcium could be obtained by similar methods. In 1808 Sir Humphry Davy finally produced the metallic element calcium from a mixture of lime and mercuric oxide by his experimental electrolysis apparatus. This was the same process he had previously used to discover several other alkali earth metals. 

Calcium Ca 1808 (London, England) Sir Humphry Davy (British) 173... 

William Cruickshank in 1787 and Adair Crawford in 1790 independently detected strontium in the mineral strontianite, small quantities of which are associated with calcium and barium minerals. They determined that the strontianite was an entirely new mineral and was different from baryta and other barium minerals known at the time. In 1808, Sir Humphry Davy isolated strontium by electrolysis of a mixture of moist strontium hydroxide or chloride with mercuric oxide, using a mercury cathode. The element was named after the town Strontian in Scotland where the mineral strontianite was found. 

Sir Humphry Davy, 1778—1829. English chemist and physicist. One of the founders of electrochemistry. Inventor of die safety lamp for miners. He was the first to isolate potassium, sodium, calcium, barium, strontium, and magnesium. Davy in England and Gay-Lussac and Thenard in France, working independently, were die first to isolate boron. 

Sir Humphry Davy isolated the metal in 1808 by the method he had used for calcium and barium (5, 3). In 1924 P. S. Danner of the University of California allowed the oxides of barium and strontium to react with magnesium or aluminum and, upon distilling, obtained both barium and strontium in a high state of purity. His method was a refinement of the one previously used by A. Guntz (33, 34). 

Within a few years, more elements were found. With the help of electricity, an English chemist, Humphry Davy, in a single year brought to light six new metals — among them sodium, potassium, calcium, and magnesium. 

The name of calcium was given to the metal hidden in limestone by its discoverer, Humphry Davy, It comes horn calx, the old Latin name for lime. 

Metals high in the reactivity series have proved very difficult to isolate. It was not until more recent times, through Sir Humphry Davy s work on electrolysis, that potassium (1807), sodium (1807), calcium (1808) and magnesium (1808) were isolated. Aluminium, the most plentiful reactive metal in the Earth s crust, was not extracted from its ore until 1827, by Friedrich Wohler (p. 74), and the extremely reactive metal rubidium was not isolated until 1861 by Robert Bunsen and Gustav Kirchhoff. 

It is interesting to note that until the new physical methods, especially the X-ray method, were developed, there was no way of rigorously proving a substance to be an element. In the early years of the science of chemistry a substance was accepted as an element so long as no reaction showing it to be a compound had been observed. At first some mistakes were made lime (calcium oxide, CaO) was considered to be an element until the English chemist Sir Humphry Davy (1778-1829) reduced it to calcium metal in 1808 and uranium dioxide, UOo, was accepted as an element from 1789 to 1841. However, by 1900 all but about a score of the elements which are now known had been recognized and correctly identified as elements. 

A Note on the Alkaline-earth Family. The early chemists gave the name earth to many non-metallic substances. Magnesium oxide and calcium oxide were found to have an alkaline Reaction, and hence were called the alkaline earths. The metals themselves (magnesium, calcium, strondum, and barium) were isolated in 1808 by Sir Humphry Davy. Beryllium was discovered in the mineral beryl (BegAl2S QOjg) in 1798 and was isolated in 1828. 

Barium was first isolated in 1808 by English chemist Sir Humphry Davy (1778-1829). In 1807 and 1808, Davy also discovered five other new elements sodium, potassium, strontium, calcium, and magnesium. All... 

Calcium metal was not prepared in a pure form until 1808 when English chemist Humphry Davy (1778—1829) passed an electric current through molten (melted) calcium chloride. 

English chemist Sir Humphry Davy isolates a number of elements in a pure form for the first time, including potassium, sodium, magnesium, barium, calcium, and strontium. 

Calcium was first recognized as an element in 1808 by Humphry Davy, and the name was given after the Latin for lime calx. Several isotopes of ealcium are known. The stable isotopes are, in order of decreasing natural abundance, " Ca (96.94%), " Ca (2.1%), Ca (0.64%), and Ca (0.145%). Ca is the only isotope with a nuclear spin (/ = ) different from zero, whieh makes it amenable to NMR studies. Ca is a radioactive isotope of some importance ()S decay 8.8 min half life). It has been used in studies of calcium localization and transport in biological systems. 

In elemental form, calcium is a relatively soft, silvery metal. Like other alkaline earths, it is too reactive to be found as a free element in nature. It was not until 1808 that Sir Humphry Davy isolated it by doing electrolysis on a mixture of lime (CaO) and mercuric oxide. Calcium s name comes from the Latin word calx, which means hme, a substance used since ancient Roman times in various ways, including as plasters for construction. 

Although calcium (Ca) metal was discovered in 1808 independently by Sir Humphry Davy and Berzelius and Pontin, the pure metal was first produced by Moissan in 1898. The name of calcium is derived from the Latin calx , meaning lime. Calcium constitutes 3.63% of the Earth s crust, and is the fifth most abundant element in the environment as well as in the human body. Due to its reactivity, it only occurs naturally in the form of its compounds for example, various magmatic rocks, carbonate (limestone), and sulfate. Calcium is indispensable for life, namely for the maintenance of structure and metabolism. Its structural roles include that of coral, the secreted shells of mollusks and, in particular, the internal skeleton of vertebrates (Hluchan and Pomerantz 2002). 

Sir Humphry Davy was an English scientist, who discovered metals such as potassium, sodium, barium, strontium, calcium and magnesium. His most famous invention was a safety lamp for use in coal mines where the highly inflammable gas, methane, is often found. Davy first proposed the name for the element with the symbol Al and called it alumium, but he changed his mind, a few years later, and called it aluminum. Many British users disliked this name, however, because it didn t conform with the ium ending given in the names of metals and adopted the name aluminium. Americans still prefer aluminum, which is why you will see this spelling in their textbooks. 

Davy, Sir Humphry (i778-i829) British chemist, who studied gases at the Pneumatic Institute in Bristol, where he discovered the anaesthetic properties of dinitrogen oxide (nitrous oxide). He moved to the Royal Institution, London, in 1801 and five years later isolated potassium and sodium by electrolysis. He also prepared barium, boron, calcium, and strontium as well as proving that chlorine and iodine are elements. In 1816 he invented the Davy lamp. 

There have been a number of major episodes in the history of chemistry when half a dozen or so elements were discovered almost at once, or within a period of a few years. Of course, some elements, such as iron, copper, gold, and other metak, have been known since antiquity. In fact, historians and archeologists refer to certain epochs in human history as the Iron Age or the Copper Age. The alchemists added several more elements to the list, including sulfur, mercury, and phosphorus. In relatively modem times, the discovery of electricity enabled chemists to isolate many of the more reactive elements that, imUke copper and iron, could not be obtained by heating their ores with carbon. The English chemist Humphry Davy seized upon the use of electricity or, more specifically, electrolysis to isolate as many as 10 elements, including calcium, barium, magnesium, sodium, and chlorine. 

A Humphry Davy was one of the first scientists to discover new elements using batteries. He discovered six elements (sodium, potassium, magnesium, calcium, strontium, and barium) this way. 

English chemist Humphry Davy discovers the elements barium and calcium. French chemist Joseph-Louis Gay-Lussac proposes Gay-Lussac s law gases combine among themselves in very simple proportions. English chemist John Dalton publishes A New System of Chemical Philosophy, in which he formulates the atomic weight theory. Davy, Gay-Lussac, and French chemist Louis-Jacques Thenard isolate the element boron. Polish chemist Jedrzej Sniadecki discovers the element ruthenium. 

Who do you suppose had a large hand in actually isolating the metals from these alkaline earths Who else but Sir Humphry Davy, fresh from his successful isolation of sodium and potassium. It turned out to be somewhat more difficult to isolate the 2A metals but, with the aid of work done by Berzelius and M. M. af Pontin, he was able, in 1808, to electrolyze moist lime in the presence of mercuric oxide to make an amalgam—that is, an alloy of mercury, which grudgingly yielded the silvery-white calcium metal. Today, calcium is prepared by the electrolysis of molten CaCl2 in the presence of Cap2 added to lower the melting point, as shown in Equation (13.2) ... 

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