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Period: period 4: Block ... Arsenic is a chemical element with the symbol As and the atomic number 33. It is a metalloid and one of the pnictogens, ...
A period 4 element is one of the chemical elements in the fourth row (or period) of the periodic table of the chemical elements.The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall ...
Period 4 includes the biologically essential elements potassium and calcium, and is the first period in the d-block with the lighter transition metals. These include iron , the heaviest element forged in main-sequence stars and a principal component of the Earth, as well as other important metals such as cobalt , nickel , and copper .
Arsenic poisoning (or arsenicosis) is a medical condition that occurs due to elevated levels of arsenic in the body. [4] If arsenic poisoning occurs over a brief period of time, symptoms may include vomiting, abdominal pain, encephalopathy, and watery diarrhea that contains blood. [1]
Elemental arsenic is toxic, as are many of its inorganic compounds; however some of its organic compounds can promote growth in chickens. [12] The lethal dose of arsenic for a typical adult is 200 mg and can cause diarrhea, vomiting, colic, dehydration, and coma. Death from arsenic poisoning typically occurs within a day. [14]
The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows ("periods") and columns ("groups"). It is an icon of chemistry and is widely used in physics and other sciences.
Arsenic only melts under a pressure of 38.6 atm, at 817 °C. [335] It is a semimetal with an electrical conductivity of around 3.9 × 10 4 S•cm −1 [336] and a band overlap of 0.5 eV. [337] [n 35] Liquid arsenic is a semiconductor with a band gap of 0.15 eV. [339] The chemistry of arsenic is predominately nonmetallic. [340]
Arsenic forms covalent bonds with most other elements. The oxide in its preferred oxidation state (As 2 O 3, +3) is amphoteric, [n 16] as is the corresponding oxoacid in aqueous solution (H 3 AsO 3) and congener sulfide (As 2 S 3). Arsenic forms a series of anionic arsenates such as Na 3 AsO 3 and PbHAsO 4, and Zintl phases such as Na 3 As, Ca ...