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Arsenic has been known since ancient times to be poisonous to humans. [16] However, a few species of bacteria are able to use arsenic compounds as respiratory metabolites. Trace quantities of arsenic have been proposed to be an essential dietary element in rats, hamsters, goats, and chickens. Research has not been conducted to determine whether ...
Robert Wilhelm Eberhard Bunsen (German:; 30 March 1811 [a] – 16 August 1899) was a German chemist.He investigated emission spectra of heated elements, and discovered caesium (in 1860) and rubidium (in 1861) with the physicist Gustav Kirchhoff. [11]
The discoveries of the 118 chemical elements known to exist as of 2025 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.
The first breakthrough in the detection of arsenic poisoning was in 1775 when Carl Wilhelm Scheele discovered a way to change arsenic trioxide to garlic-smelling arsine gas (AsH 3), by treating it with nitric acid (HNO 3) and combining it with zinc. [3] As 2 O 3 + 6 Zn + 12 HNO 3 → 2 AsH 3 + 6 Zn(NO 3) 2 + 3 H 2 O
Carl Wilhelm Scheele (German:, Swedish: [ˈɧêːlɛ]; 9 December 1742 – 21 May 1786 [2]) was a German Swedish [3] pharmaceutical chemist.. Scheele discovered oxygen (although Joseph Priestley published his findings first), and identified molybdenum, tungsten, barium, nitrogen, and chlorine, among others.
It was recognised as an element by Guyton de Morveau, Lavoisier, Berthollet, and Fourcroy in 1787. [6] The earliest gold artifacts were discovered at the site of Wadi Qana in the Levant. [13] Silver is estimated to have been discovered in Asia Minor shortly after copper and gold. [14] There is evidence that iron was known from before 5000 BC. [15]
He is credited with the discovery of the element arsenic [25] and experimented with photosensitive chemicals, including silver nitrate. [26] [27] He did believe that stones had occult properties, as he related in his work De mineralibus. However, there is scant evidence that he personally performed alchemical experiments.
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 ...