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Arsenic (As)

Arsenic (As) is element 33 of the periodic table, a metalloid in period 4 and group 15. Its standard atomic weight is 74.921595, so one mole of arsenic atoms has a mass of 74.921595 g. At room temperature it is a solid; it melts at 816.85 °C and boils at 613.85 °C.

33 As Arsenic 74.921595

Period 4, group 15 · Metalloid

← Ge Germanium Se Selenium →

Atomic number	33
Symbol	As
Standard atomic weight	74.921595
Molar mass	74.921595 g/mol
Category	Metalloid
Group	15
Period	4
Block	p-block
Electron configuration	[Ar] 4s² 3d¹⁰ 4p³
Oxidation states	+5, +3, −3
Electronegativity (Pauling)	2.18
Atomic radius (van der Waals)	185 pm
First ionisation energy	9.815 eV (947 kJ/mol)
Electron affinity	0.81 eV
State at room temperature	Solid
Melting point	1090 K (816.85 °C)
Boiling point	887 K (613.85 °C)
Density	5.776 g/cm³
Discovered	Known since antiquity

Group 15

N · Nitrogen P · Phosphorus Sb · Antimony Bi · Bismuth Mc · Moscovium

Calculate with Arsenic

Molar mass of As Balance an equation Grams, moles and particles Whole periodic table

Atomic weight: IUPAC CIAAW standard atomic weight. Other properties: PubChem (U.S. National Library of Medicine, public domain). Values such as melting point and radius depend on how they were measured; check a data book for precise work.