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As Arsenic
Element Information, Facts, Properties, Trends, Uses, Comparison with other elements

33
As
Arsenic
Element 33 of Periodic table is Arsenic with atomic number 33, atomic weight 74.9216. Arsenic, symbol As, has a Simple Trigonal structure and Silver color. Arsenic is a Metalloid element. It is part of group 15 (nitrogen family). Know everything about Arsenic Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.
33 As - Arsenic | SchoolMyKids

Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. Arsenic is a Metalloid.

It belongs to group 15 of the periodic table having trivial name pentels, pnictogens*. It got its trivial name from pentels from Greek penta (five, V).

Arsenic Facts

Read key information and facts about element Arsenic

NameArsenic
Atomic Number33
Atomic SymbolAs
Atomic Weight74.9216
PhaseSolid
ColorSilver
Appearancemetallic grey
ClassificationMetalloid
Group in Periodic Table15
Group Namenitrogen family
Period in Periodic Tableperiod 4
Block in Periodic Tablep -block
Electronic Configuration[Ar] 3d10 4s2 4p3
Electronic Shell Structure (Electrons per shell)2, 8, 18, 5
Melting Point1090 K
Boiling Point887 K
CAS NumberCAS7440-38-2
123456789101112131415161718
1
1
H
Hydrogen
1.008

Atomic #

Electronic Shell #

Symbol
Name
Atomic Weight
HGas
HgLiquid
CSolid
Metals
Metalloids
NonMetals
Alkali metals
Alkali earth metals
Lanthanoids
Transition metals
Post-transition metals
Other nonmetals
Halogens
Nobel gas
Actinoids
2
He
Helium
4.003
2
3
Li
Lithium
6.941
4
Be
Beryllium
9.012
5
B
Boron
10.811
6
C
Carbon
12.011
7
N
Nitrogen
14.007
8
O
Oxygen
15.999
9
F
Fluorine
18.998
10
Ne
Neon
20.180
3
11
Na
Sodium
22.990
12
Mg
Magnesium
24.305
13
Al
Aluminium
26.982
14
Si
Silicon
28.085
15
P
Phosphorus
30.974
16
S
Sulfur
32.065
17
Cl
Chlorine
35.453
18
Ar
Argon
39.948
4
19
K
Potassium
39.098
20
Ca
Calcium
40.078
21
Sc
Scandium
44.956
22
Ti
Titanium
47.867
23
V
Vanadium
50.941
24
Cr
Chromium
51.996
25
Mn
Manganese
54.938
26
Fe
Iron
55.845
27
Co
Cobalt
58.933
28
Ni
Nickel
58.693
29
Cu
Copper
63.546
30
Zn
Zinc
65.409
31
Ga
Gallium
69.723
32
Ge
Germanium
72.640
33
As
Arsenic
74.922
34
Se
Selenium
78.960
35
Br
Bromine
79.904
36
Kr
Krypton
83.798
5
37
Rb
Rubidium
85.468
38
Sr
Strontium
87.620
39
Y
Yttrium
88.906
40
Zr
Zirconium
91.224
41
Nb
Niobium
92.906
42
Mo
Molybdenum
95.940
43
Tc
Technetium
98
44
Ru
Ruthenium
101.070
45
Rh
Rhodium
102.906
46
Pd
Palladium
106.420
47
Ag
Silver
107.868
48
Cd
Cadmium
112.411
49
In
Indium
114.818
50
Sn
Tin
118.710
51
Sb
Antimony
121.760
52
Te
Tellurium
127.600
53
I
Iodine
126.904
54
Xe
Xenon
131.293
6
55
Cs
Cesium
132.905
56
Ba
Barium
137.327
57 - 71
La - Lu
Lanthanides
72
Hf
Hafnium
178.490
73
Ta
Tantalum
180.948
74
W
Tungsten
183.840
75
Re
Rhenium
186.207
76
Os
Osmium
190.230
77
Ir
Iridium
192.217
78
Pt
Platinum
195.078
79
Au
Gold
196.967
80
Hg
Mercury
200.590
81
Tl
Thallium
204.383
82
Pb
Lead
207.200
83
Bi
Bismuth
208.980
84
Po
Polonium
209
85
At
Astatine
210
86
Rn
Radon
222
7
87
Fr
Francium
223
88
Ra
Radium
226
89 - 103
Ac - Lr
Actinides
104
Rf
Rutherfordium
261
105
Db
Dubnium
262
106
Sg
Seaborgium
266
107
Bh
Bohrium
264
108
Hs
Hassium
277
109
Mt
Meitnerium
268
110
Ds
Darmstadtium
281
111
Rg
Roentgenium
272
112
Cn
Copernicium
285
113
Nh
Nihonium
284
114
Fl
Flerovium
289
115
Mc
Moscovium
288
116
Lv
Livermorium
292
117
Ts
Tennessine
294
118
Og
Oganesson
294
Lanthanides
57
La
Lanthanum
138.905
58
Ce
Cerium
140.116
59
Pr
Praseodymium
140.908
60
Nd
Neodymium
144.240
61
Pm
Promethium
145
62
Sm
Samarium
150.360
63
Eu
Europium
151.964
64
Gd
Gadolinium
157.250
65
Tb
Terbium
158.925
66
Dy
Dysprosium
162.500
67
Ho
Holmium
164.930
68
Er
Erbium
167.259
69
Tm
Thulium
168.934
70
Yb
Ytterbium
173.040
71
Lu
Lutetium
174.967
Actinides
89
Ac
Actinium
227
90
Th
Thorium
232.038
91
Pa
Protactinium
231.036
92
U
Uranium
238.029
93
Np
Neptunium
237
94
Pu
Plutonium
244
95
Am
Americium
243
96
Cm
Curium
247
97
Bk
Berkelium
247
98
Cf
Californium
251
99
Es
Einsteinium
252
100
Fm
Fermium
257
101
Md
Mendelevium
258
102
No
Nobelium
259
103
Lr
Lawrencium
262

How to Locate Arsenic on Periodic Table

Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 33 to find Arsenic on periodic table.

Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Arsenic on periodic table look for cross section of group 15 and period 4 in the modern periodic table.

Arsenic History

The element Arsenic was discovered by Arabic alchemist in year ca. 800 AD . Arsenic was first isolated by in . Arsenic derived its name English word (Latin arsenicum).

First isolated by Jabir ibn Hayyan , an Arabian alchemist. Albertus Magnus was the first European to isolate the element.

Arsenic Presence: Abundance in Nature and Around Us

The table below shows the abundance of Arsenic in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.

 ppb by weight (1ppb =10^-7 %)ppb by atoms (1ppb =10^-7 %)
Abundance in Universe80.1
Abundance in Sun--
Abundance in Meteorites1800460
Abundance in Earth's Crust2100580
Abundance in Oceans2.30.19
Abundance in Humans504

Crystal Structure of Arsenic

The solid state structure of Arsenic is Simple Trigonal.

The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.

Unit Cell Parameters

The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)

abc
375.98 pm375.98 pm1054.75 pm

and the angles between them Lattice Angles (alpha, beta and gamma).

alphabetagamma
π/2 π/2 2 π/3

The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.

The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.

Space Group NameR_ 3m 33 As Arsenic - Crystal Structure | SchoolMyKids
Oxidation StatesSpace Group Number166
Crystal StructureSimple Trigonal

Arsenic Atomic and Orbital Properties

Arsenic atoms have 33 electrons and the electronic shell structure is [2, 8, 18, 5] with Atomic Term Symbol (Quantum Numbers) 4S3/2.

Atomic Number33
Number of Electrons (with no charge)33
Number of Protons33
Mass Number75
Number of Neutrons42
Shell structure (Electrons per energy level)2, 8, 18, 5
Electron Configuration[Ar] 3d10 4s2 4p3
Valence Electrons4s2 4p3
Valence (Valency)5
Main Oxidation States-3, 3, 5
Oxidation States-3, -2, -1, 0, 1, 2, 3, 4, 5
Atomic Term Symbol (Quantum Numbers)4S3/2

Bohr Atomic Model of Arsenic - Electrons per energy level

33 As Arsenic - Electron Shell Structure | SchoolMyKids
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Ground State Electronic Configuration of Arsenic - neutral Arsenic atom

Abbreviated electronic configuration of Arsenic

The ground state abbreviated electronic configuration of Neutral Arsenic atom is [Ar] 3d10 4s2 4p3. The portion of Arsenic configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Ar]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. This is important as it is the Valence electrons 4s2 4p3, electrons in the outermost shell that determine the chemical properties of the element.

Unabbreviated electronic configuration of neutral Arsenic

Complete ground state electronic configuration for the Arsenic atom, Unabbreviated electronic configuration

1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p3

Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.

  • As per the Aufbau principle the electrons will occupy the orbitals having lower energies before occupying higher energy orbitals. According to this principle, electrons are filled in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…
  • The Pauli exclusion principle states that a maximum of two electrons, each having opposite spins, can fit in an orbital.
  • Hund's rule states that every orbital in a given subshell is singly occupied by electrons before a second electron is filled in an orbital.
  • Electron configuration of Arsenic
    Atomic Structure of Arsenic

    Arsenic atomic radius is 114 pm, while it's covalent radius is 119 pm.

    Atomic Radius Calculated

    114 pm (1.14 Å)

    Atomic Radius Empirical

    115 pm (1.15 Å)

    Atomic Volume12.95 cm3/mol
    Covalent Radius119 pm (1.19 Å)
    Van der Waals Radius185 pm
    Neutron Cross Section4.3
    Neutron Mass Absorption 0.002

    Atomic Spectrum of Arsenic

    Atomic Spectrum of Arsenic | SchoolMyKids

    Arsenic Chemical Properties: Arsenic Ionization Energies and electron affinity

    The electron affinity of Arsenic is 78 kJ/mol.

    Valence5
    Electronegativity2.18
    ElectronAffinity78 kJ/mol

    Ionization Energy of Arsenic

    Refer to table below for Ionization energies of Arsenic

    Ionization energy numberEnthalpy - kJ/mol
    1st947
    2nd1798
    3rd2735
    4th4837
    5th6043
    6th12310

    Arsenic Physical Properties

    Refer to below table for Arsenic Physical Properties

    Density5.727 g/cm3(when liquid at m.p density is $5.22 g/cm3)
    Molar Volume12.95 cm3/mol

    Elastic Properties

    Young Modulus8
    Shear Modulus-
    Bulk Modulus 22 GPa
    Poisson Ratio-

    Hardness of Arsenic - Tests to Measure of Hardness of Element

    Mohs Hardness3.5 MPa
    Vickers Hardness-
    Brinell Hardness1440 MPa

    Arsenic Electrical Properties

    Arsenic is Conductor of electricity. Refer to table below for the Electrical properties ofArsenic

    Electrical Conductivity3300000 S/m
    Resistivity3e-7 m Ω
    Superconducting Point-

    Arsenic Heat and Conduction Properties

    Thermal Conductivity50 W/(m K)
    Thermal Expansion-

    Arsenic Magnetic Properties

    Magnetic TypeDiamagnetic
    Curie Point-
    Mass Magnetic Susceptibility-3.9e-9 m3/kg
    Molar Magnetic Susceptibility-2.92e-10 m3/mol
    Volume Magnetic Susceptibility-0.0000223

    Optical Properties of Arsenic

    Refractive Index1.001552

    Acoustic Properties of Arsenic

    Speed of Sound-

    Arsenic Thermal Properties - Enthalpies and thermodynamics

    Refer to table below for Thermal properties of Arsenic

    Melting Point1090 K (816.85°C, 1502.3300000000002 °F)
    Boiling Point887 K (613.85°C, 1136.93 °F)
    Critical Temperature-
    Superconducting Point-

    Enthalpies of Arsenic

    Heat of Fusion27.7 kJ/mol
    Heat of Vaporization32.4 kJ/mol
    Heat of Combustion-

    Arsenic Isotopes - Nuclear Properties of Arsenic

    Arsenic has 33 isotopes, with between 60 and 92 nucleons. Arsenic has 1 stable naturally occuring isotopes.

    Isotopes of Arsenic - Naturally occurring stable Isotopes: 75As.

    IsotopeZNIsotope Mass% AbundanceT halfDecay Mode
    60As332760Synthetic
    61As332861Synthetic
    62As332962Synthetic
    63As333063Synthetic
    64As333164Synthetic
    65As333265Synthetic
    66As333366Synthetic
    67As333467Synthetic
    68As333568Synthetic
    69As333669Synthetic
    70As333770Synthetic
    71As333871Synthetic
    72As333972Synthetic
    73As334073Synthetic
    74As334174Synthetic
    75As334275100%Stable
    76As334376Synthetic
    77As334477Synthetic
    78As334578Synthetic
    79As334679Synthetic
    80As334780Synthetic
    81As334881Synthetic
    82As334982Synthetic
    83As335083Synthetic
    84As335184Synthetic
    85As335285Synthetic
    86As335386Synthetic
    87As335487Synthetic
    88As335588Synthetic
    89As335689Synthetic
    90As335790Synthetic
    91As335891Synthetic
    92As335992Synthetic

    Regulatory and Health - Health and Safety Parameters and Guidelines

    Database Search

    List of unique identifiers to search the element in various chemical registry databases

    DatabaseIdentifier number
    CAS Number - Chemical Abstracts Service (CAS)CAS7440-38-2
    RTECS Number{N/A, RTECSCG0525000, N/A}
    CID Number {CID5359596, CID5359596, CID139279}
    Gmelin Number-
    NSC Number-