Davy, Humphry elements isolated

Sir Humphry Davy (1778-1829) isolated the element by electrolysis of molten caustic soda (NaOH). 

Sir Humphry Davy attempted to isolate this unidentified element through electrolysis—but failed. It was not until 1824 that Jons Jakob Berzehus (1779—1848), who had earlier discovered cerium, osmium, and iridium, became the first person to separate the element silicon from its compound molecule and then identify it as a new element. Berzehus did this by a two-step process that basically involved heating potassium metal chips with a form of silica (SiF = silicon tetrafluoride) and then separating the resulting mixture of potassium fluoride and silica (SiF + 4K —> 4KF + Si). Today, commercial production of sihcon features a chemical reaction (reduction) between sand (SiO ) and carbon at temperatures over 2,200°C (SiO + 2C + heat— 2CO + Si). 

The spectacular success (in 1807) of Humphry Davy, then aged 29 y, in isolating metallic potassium by electrolysis of molten caustic potash (KOH) is too well known to need repeating in detail." Globules of molten sodium were similarly prepared by him a few days later from molten caustic soda. Earlier experiments with aqueous solutions had been unsuccessful because of the great reactivity of these new elements. The names chosen by Davy reflect the sources of the elements. 

Boron (Buraq in Arabic/Burah in Persian, which is the word for white, the color being attributed to borax (sodium tetraborate, Na2B4O7.10H2O)) was discovered in 1808 independently by the British Chemist, Sir Humphry Davy, and two French chemists, Joseph Louis Gay-Lussac and Loius Jacques Thenard.1 They isolated boron in 50% purity by the reduction of boric acid with sodium or magnesium. The Swedish chemist Jons Jakob Berzilius identified boron as an element in 1824. The first pine sample of boron was produced by the American chemist William Weintraub in 1909. Boron does not appear in nature in elemental form, but is found in its compounded... 

Magnesium (Mg, [Ne]3.v2), name, and symbol, from the Greek word Magnesia a city of Thessaly. Recognized as an element (1755) by Joseph Black, isolated (1808) by Humphry Davy. 

The basis for the claim of discovery of an element has varied over the centuries. The method of discovery of the chemical elements in the late eightenth and the early nineteenth centuries used the properties of the new sustances, their separability, the colors of their compounds, the shapes of their crystals and their reactivity to determine the existence of new elements. In those early days, atomic weight values were not available, and there was no spectral analysis that would later be supplied by arc, spark, absorption, phosphorescent or x-ray spectra. Also in those days, there were many claims, e.g., the discovery of certain rare earth elements of the lanthanide series, which involved the discovery of a mineral ore, from which an element was later extracted. The honor of discovery has often been accorded not to the person who first isolated the element but to the person who discovered the original mineral itself, even when the ore was impure and that ore actually contained many elements. The reason for this is that in the case of these rare earth elements, the earth now refers to oxides of a metal not to the metal itself This fact was not realized at the time of their discovery, until the English chemist Humphry Davy showed that earths were compounds of oxygen and metals in 1808. 

Strontium - the atomic number is 38 and the chemical symbol is Sr. The name derives from Strontian, a town in Scotland . The mineral strontianite is found in mines in Strontian. The element was discovered by the Scottish chemist and physician Thomas Charles Hope in 1792 observing the brilliant red flame color of strontium. It was first isolated by the English chemist Humphry Davy in 1808. 

In 1787 William Cruikshank (1745-1795) isolated, but did not identify, strontium from the mineral strontianite he examined. In 1790 Dr. Adair Crawford (1748—1794), an Irish chemist, discovered strontium by accident as he was examining barium chloride. He found a substance other than what he expected and considered it a new mineral. He named the new element strontium and its mineral strontianite after a village in Scotland. In 1808 Sir Humphry Davy treated the ore with hydrochloric acid, which produced strontium chloride. He then mixed mercury oxide with the strontium chloride to form an amalgam alloy of the two metals that collected at the cathode of his electrolysis apparatus. He heated the resulting substance to vaporize the mercury, leaving the strontium metal as a deposit. 

Chemists did not discover the mineral witherite (BaCO ) until the eighteenth century. Carl Wilhelm Scheele (1742—1786) discovered barium oxide in 1774, but he did not isolate or identify the element barium. It was not until 1808 that Sir Humphry Davy used molten barium compounds (baryta) as an electrolyte to separate, by electrolysis, the barium cations, which were deposited at the negative cathode as metallic barium. Therefore, Davy received the credit for bariums discovery. 

Potassium was first isolated as a free metal in 1807 by Sir Humphry Davy. It was the first alkali metal to be discovered, produced by electrolysis of potassium carbonate (potash). The element was earlier called Kalium, derived from the Arabic word qili, meaning grass wort, the ash of which was a source of potash. The element derived its symbol K from Kalium. The English name potassium came from potash (pot ash), the carbonate salt of the metal. 

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. 

Joseph Black recognized Mg as an element, and in 1808, Humphry Davy electrolytically made Mg amalgam. The metal was isolated by Antoine Bussy in 1828 by reduction of MgCl2 with K. 

Although Sir Humphry Davy felt certain that silica is not an element, he was unable to decompose it with his powerful voltaic pile, and was also unsuccessful in his attempts to isolate silicon by passing potassium vapor over red-hot silica. Gay-Lussac and Thenard observed that silicon tetrafluoride and potassium react violently when the metal is heated, and that a reddish brown, combustible solid is obtained. This was probably very impure amorphous silicon (37, 39). 

Sir Humphry Davy, 1778-1829. British chemist who isolated the alkali and alkaline earth metals and boron, and proved that chlorine is an element. Gay-Lussac and Thenard isolated boron independently at about the same time. 

Aluminium was first named (although not isolated) by Sir Humphry Davy, who originally called it alumium (1808) because it was found in alum, a name that had been extant since at least the 14th century. He later called it aluminum (1812), but others soon changed it to aluminium, in order to harmonize it with the many other elements whose... 

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... 

Potassium is so active that it never occurs free in nature. It always occurs in compounds, combined with other elements. It was first prepared in pure form in 1807 by English chemist Sir Humphry Davy (1778—1829). Davy used a new method of isolating elements that he had invented called electrolysis. In electrolysis, an electric current is passed through a molten (melted) compound. The electrical current breaks the compound into its elements. 

The next step may be to isolate the element, either in its pure form or, more commonly, as a compound, such as the oxide or sulfide of the new element. Finally, someone is able to prepare a pure sample of the element, which the world then sees for the first time. An example of this sequence of events can be seen in the elements that make up groups 1 and 2 of the periodic table. Most of those elements were known in one form or another for centuries. But it was not until the early 1800s that Sir Humphry Davy found a method for isolating the pure elements from their oxides. 

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 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. 

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