Arsenic

Arsenic,  ₃₃As

General properties
Name, seembol	arsenic, As
Appearance	metallic grey
Pronunciation	/ˈɑrsɨnɪk/ AR-sə-nik, also /ɑrˈsɛnɪk/ ar-SEN-ik when attributive
Arsenic in the periodic cairt
P ↑ As ↓ Sb germanium ← arsenic → selenium
Atomic nummer (Z)	33
Group, block	group 15 (pnictogens), p-block
Period	period 4
Element category	metalloid
Staundart atomic wicht (±) (Ar)	74.921595(6)
Electron configuration	[Ar] 4s2 3d10 4p3
per shell	2, 8, 18, 5
Pheesical properties
Phase	solid
Sublimation pynt	887 K ​(615 °C, ​1137 °F)
Density near r.t.	5.727 g/cm3
when liquid, at m.p.	5.22 g/cm3
Triple pynt	1090 K, ​3628 kPa
Creetical pynt	1673 K, ? MPa
Heat of fusion	(grey) 24.44 kJ/mol
Heat o	? 34.76 kJ/mol
Molar heat capacity	24.64 J/(mol·K)
pressur P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 553 596 646 706 781 874
Atomic properties
Oxidation states	5, 3, 2, 1, -3 ​mildly acidic oxide
Electronegativity	Pauling scale: 2.18
energies	(more)
Atomic radius	empirical: 119 pm
Covalent radius	119±4 pm
Van der Waals radius	185 pm
Miscellanea
Crystal structur	​trigonal
Thermal conductivity	50.2 W/(m·K)
Electrical resistivity	333 n Ω·m (at 20 °C)
Magnetic orderin	diamagnetic
Young's modulus	8 GPa
Bulk modulus	22 GPa
Mohs haurdness	3.5
Brinell haurdness	1440 MPa
CAS Nummer	7440-38-2
History
Discovery	Early Bronze Age (2500 BC)
First isolation	Albertus Magnus (1250)
Most stable isotopes of arsenic
iso NA hauf-life DM DE (MeV) DP 73As syn 80.3 d ε - 73Ge γ 0.05D, 0.01D, e - 74As syn 17.78 d ε - 74Ge β+ 0.941 74Ge γ 0.595, 0.634 - β− 1.35, 0.717 74Se 75As 100% 75As is stable wi 42 neutrons

Arsenic is a chemical element wi seembol As an atomic nummer 33. Arsenic occurs in mony minerals, uisually in conjunction wi sulfur an metals, an an aa as a pure elemental crystal. It wiis first documentit bi Albertus Magnus in 1250. Arsenic is a metalloid. It can exist in various allotropes, altho anly the gray furm haes important uise in industry.