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Platinum also has 38 synthetic isotopes ranging in atomic mass from 165 to 208, making the total number of known isotopes 44. The least stable of these are 165 Pt and 166 Pt, with half-lives of 260 μs, whereas the most stable is 193 Pt with a half-life of 50 years. Most platinum isotopes decay by some combination of beta decay and alpha decay ...
The discoveries of the 118 chemical elementsknown to exist as of 2024 are presented here in chronological order. The elements are listed generally in the order in which each was first defined as the pure element, as the exact date of discovery of most elements cannot be accurately determined. There are plans to synthesize more elements, and it ...
Humphry Davy had discovered a few years earlier that a hot platinum wire lit up in a mixture of coal gas and air. [10]) This release of energy from oxidation of the compounds, without flame, and without change in the platinum itself, was a sign of the catalytic property of platinum investigated later by Johann Döbereiner and other chemists.
We now apply Thomson's equations described above to an alpha particle colliding with a gold atom, using the following values: q g = positive charge of the gold atom = 79 q e = 1.26 × 10 −17 C; q a = charge of the alpha particle = 2 q e = 3.20 × 10 −19 C; q e = elementary charge = 1.602 × 10 −19 C; R = radius of the gold atom = 1.44 × ...
Döbereiner is also known for his discovery of furfural, [5] for his work concerning the use of platinum as a catalyst, and for the invention of a lighter, known as Döbereiner's lamp. [6] By 1828 hundreds of thousands of these lighters had been mass produced by the German manufacturer Gottfried Piegler in Schleiz. [7]
After Rutherford's discovery, subsequent research determined the atomic structure which led to Rutherford's gold foil experiment. Scientists eventually discovered that atoms have a positively charged nucleus (with an atomic number of charges) in the center, with a radius of about 1.2 × 10 −15 meters × [atomic mass number] 1 ⁄ 3. Electrons ...
During the Age of Discovery, Spain sponsored and financed the transatlantic voyages of the Italian navigator Christopher Columbus, which from 1492 to 1504 marked the start of colonization in the Americas, and the expedition of the Portuguese explorer Ferdinand Magellan to open a route from the Atlantic Ocean to the Pacific, which later achieved ...
October 18 is celebrated each year in the Last Frontier as Alaska Day, an official state holiday. Read On The Fox News App. ... with the discovery of vast troves of gold in Alaska.