Airsenic is a chemical element wi symbol As an atomic nummer 33. Airsenic occurs in mony minerals , uisually in conjunction wi sulfur an metals , an an aa as a pure elemental crystal. It wis first documentit bi Albertus Magnus in 1250.[7] Airsenic is a metalloid . It can exist in sindry allotropes , altho anly the gray furm haes important uise in industry.
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Airsenic, 33 As Airsenic Pronunciation Appearance metallic grey Standard atomic weight A r, std (As)7001749215950000000♠ 74.921595 (6)[1] Airsenic in the periodic cairt
P ↑As ↓Sb
germanium ← airsenic → selenium
Atomic nummer (Z ) 33 Group group 15 (pnictogens) Period period 4 Block p-block Element category Metalloid Electron confeeguration [ Ar ] 3d10 4s2 4p3 Electrons per shell 2, 8, 18, 5 Pheesical properties Phase at STP solit 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 Treeple pynt 1090 K, 3628[2] kPa Creetical pynt 1673 K, ? MPa Heat o fusion (grey) 24.44 kJ/mol Heat o vapourisation ? 34.76 kJ/mol Molar heat capacity 24.64 J/(mol·K) Vapour 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 −3 , −2, −1, 0,[3] +1,[4] +2, +3 , +4, +5 (a mildly acidic oxide)Electronegativity Pauling scale: 2.18 Ionisation energies Atomic radius empirical: 119 pm Covalent radius 119±4 pm Van der Waals radius 185 pm Colour lines in a spectral range Spectral lines o airsenicIther properties Naitural occurrence primordial Creestal structur trigonal [5] Thermal conductivity 50.2 W/(m·K) Electrical resistivity 333 n Ω·m (at 20 °C) Magnetic orderin diamagnetic [6] Young's modulus 8 GPa Bulk modulus 22 GPa Mohs haurdness 3.5 Brinell haurdness 1440 MPa CAS Nummer 7440-38-2 History Diskivery Early Bronze Age (2500 BC ) First isolation Albertus Magnus (1250)Main isotopes o airsenic
Iso tope
Abun dance
Hauf-life (t 1/2 )
Decay mode
Pro duct
73 As
syn
80.3 d
ε
73 Ge
γ
-
74 As
syn
17.78 d
ε
74 Ge
β+
74 Ge
γ
-
β−
74 Se
75 As
100%
stable
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