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Arsenic occurs in nature as one stable isotope, 75 As, and is therefore called a monoisotopic element. [28] As of 2024, at least 32 radioisotopes have also been synthesized, ranging in atomic mass from 64 to 95. [29] [30] The most stable of these is 73 As with a half-life of 80.30 days.
Arsenic compounds have been known for at least 5000 years, and the ancient Greek Theophrastus recognized the arsenic minerals called realgar and orpiment. Elemental arsenic was discovered in the 13th century by Albertus Magnus. [14] Antimony was well known to the ancients. A 5000-year-old vase made of nearly pure antimony exists in the Louvre.
Perey discovered it as a decay product of 227 Ac. [177] Francium was the last element to be discovered in nature, rather than synthesized in the lab, although four of the "synthetic" elements that were discovered later (plutonium, neptunium, astatine, and promethium) were eventually found in trace amounts in nature as well. [178]
In its standard state arsine is a colorless, denser-than-air gas that is slightly soluble in water (2% at 20 °C) [1] and in many organic solvents as well. [citation needed] Arsine itself is odorless, [5] but it oxidizes in air and this creates a slight garlic or fish-like scent when the compound is present above 0.5 ppm. [6]
To give provisional names to his predicted elements, Dmitri Mendeleev used the prefixes eka- / ˈ iː k ə-/, [note 1] dvi- or dwi-, and tri-, from the Sanskrit names of digits 1, 2, and 3, [3] depending upon whether the predicted element was one, two, or three places down from the known element of the same group in his table.
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
This is an accepted version of this page This is the latest accepted revision, reviewed on 12 November 2024. Periodic table of the elements with eight or more periods Extended periodic table Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium ...
Arsenic is a metalloid with an atomic number of 33, and its common oxidation states are +3 or +5, as arsenate(As III) and arsenite(As V). [12] Arsenic is primarily found as organic arsenic compounds, inorganic arsenic compounds, and arsine gas.