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Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium.
Scheele showed that scheelite (then called tungsten) was a salt of calcium with a new acid, which he called tungstic acid. The Elhuyars obtained tungstic acid from wolframite and reduced it with charcoal, naming the element "volfram". [1] [87] Since that time both names, tungsten and wolfram, have been used depending on language. [1]
When Davy heard that Berzelius and Pontin prepared calcium amalgam by electrolyzing lime in mercury, he tried it himself. Davy was successful, and discovered calcium in 1808 by electrolyzing a mixture of lime and mercuric oxide. [68] [69] He worked with electrolysis throughout his life and, in 1808, he isolated magnesium, strontium [70] and ...
A coronary CT calcium scan is a computed tomography (CT) scan of the heart for the assessment of severity of coronary artery disease. Specifically, it looks for calcium deposits in atherosclerotic plaques in the coronary arteries that can narrow arteries and increase the risk of heart attack. [ 1 ]
Sir Humphry Davy, 1st Baronet, FRS, MRIA, FGS (17 December 1778 – 29 May 1829) was a British chemist and inventor who invented the Davy lamp and a very early form of arc lamp.
A ½-cup serving of firm tofu in calcium solution contains a whopping 861 milligrams of calcium—making it an excellent source—along with 22 grams of protein.
This is an accepted version of this page This is the latest accepted revision, reviewed on 17 November 2024. Development of the table of chemical elements The American chemist Glenn T. Seaborg —after whom the element seaborgium is named—standing in front of a periodic table, May 19, 1950 Part of a series on the Periodic table Periodic table forms 18-column 32-column Alternative and ...
A carbide lamp or acetylene gas lamp is a simple lamp that produces and burns acetylene (C 2 H 2), which is created by the reaction of calcium carbide (CaC 2) with water (H 2 O). [ 1 ] Acetylene gas lamps were used to illuminate buildings, as lighthouse beacons, and as headlights on motor-cars and bicycles.