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. Trivial name of Arsenic is pentels, pnictogens*. Know everything about Arsenic Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.
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.
Read key information and facts about element Arsenic
Name | Arsenic |
Atomic Number | 33 |
Atomic Symbol | As |
Atomic Weight | 74.9216 |
Phase | Solid |
Color | Silver |
Classification | metalloid |
Group in Periodic Table | 15 |
Group Name | nitrogen family |
Period in Periodic Table | 4 |
Block in Periodic Table | p-block |
Electronic Configuration | [Ar] 3d10 4s2 4p3 |
Melting Point | 817 °C |
Boiling Point | 614 °C |
Electronic Shell Structure | [2, 8, 18, 5] |
CAS Number | CAS7440-38-2 |
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.
The element Arsenic was discovered by Bronze Age in year 1250 in unknown place . Arsenic derived its name English word (Latin arsenicum)
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 %) | |
---|---|
Abundance in Universe | 8×10-7% |
Abundance in Sun | N/A |
Abundance in Meteorites | 1.8e-06 |
Abundance in Earth's Crust | 2.1e-06 |
Abundance in Oceans | 2.3×10-7% |
Abundance in Humans | 5×10-6% |
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.
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)
a | b | c |
---|---|---|
375.98 | 375.98 | 1054.75 pm |
and the angles between them Lattice Angles (alpha, beta and gamma).
alpha | beta | gamma |
---|---|---|
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 Name | R_ 3m |
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Space Group Number | 166 | |
Crystal Structure | Simple Trigonal |
Arsenic atoms have 33 electrons and the electronic shell structure is [2, 8, 18, 5] with Atomic Term Symbol (Quantum Numbers) 4S3/2.
Atomic Number | 33 |
Number of Electrons (with no charge) | 33 |
Number of Protons | 33 |
Mass Number | 75 |
Number of Neutrons | 42 |
Shell structure (Electrons per energy level) | [2, 8, 18, 5] |
Electron Configuration | [Ar] 3d10 4s2 4p3 |
Valence Electrons | 4s2 4p3 |
Oxidation State |
-3;-2;-1
1;2;3;4;5 |
Atomic Term Symbol (Quantum Numbers) | 4S3/2 |
Shell Structure of Arsenic - Electrons per energy level
n | s | p | d | f | |
---|---|---|---|---|---|
1 | K | 2 | |||
2 | L | 2 | 6 | ||
3 | M | 2 | 6 | 10 | |
4 | N | 2 | 3 |
The ground state 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 3d10 4s2 4p3, electrons in the outermost shell that determine the chemical properties of the element.
Complete ground state electronic configuration for the Arsenic atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p3
Arsenic atomic radius is 114 pm, while it's covalent radius is 119 pm.
Atomic Radius |
114 pm (1.14 Å) |
Atomic Volume | 13.0821721669 cm3 |
Covalent Radius | 119 pm (1.19 Å) |
Van der Waals Radius | 185 pm |
Neutron Cross Section | 4.3 σa/barns |
The electron affinity of Arsenic is 78 kJ/mol
Valence | 5 |
Electronegativity | 2.18 |
ElectronAffinity | 78 kJ/mol |
Refer to table below for Ionization energies of Arsenic
Ionization energy number | Enthalpy - kJ/mol |
---|---|
1 | 947 |
2 | 1798 |
3 | 2735 |
4 | 4837 |
5 | 6043 |
6 | 12310 |
Refer to below table for Arsenic Physical Properties
Density | 5.727 g/cm3 |
Molar Volume | 13.0821721669 cm3 |
Young Modulus | 8 GPa |
Shear Modulus | N/A |
Bulk Modulus | 22 GPa |
Poisson Ratio | N/A |
Mohs Hardness | 3.5 MPa |
Vickers Hardness | N/A |
Brinell Hardness | 1440 MPa |
Arsenic is Conductor of electricity. Refer to table below for the Electrical properties of Arsenic
Electrical Conductivity | 3.3×106 S/m |
Resistivity | 3×10-7 m Ω |
Superconducting Point | N/A |
Thermal Conductivity | 50 W/(m K) |
Thermal Expansion | N/A |
Magnetic Type | Diamagnetic |
Curie Point | N/A |
Mass Magnetic Susceptibility | -3.9×10-9 |
Molar Magnetic Susceptibility | -2.92×10-10 |
Volume Magnetic Susceptibility | -2.23e-05 |
Refractive Index | 1.001552 |
Speed of Sound | N/A |
Refer to table below for Thermal properties of Arsenic
Melting Point | 1090 K (817 °C) |
Boiling Point | 887 K (614 °C) |
Critical Temperature | N/A |
Superconducting Point | N/A |
Heat of Fusion | 27.7 kJ/mol |
Heat of Vaporization | 32.4 kJ/mol |
Heat of Combustion | {"N/A", "N/A", "N/A"} J/(kg K) |
Isotopes of rhodium. Naturally occurring Arsenic has 1 stable isotope - 75As.
Isotope | Isotope Mass | % Abundance | T half | Decay Mode |
---|---|---|---|---|
60As | ||||
61As | ||||
62As | ||||
63As | ||||
64As | ||||
65As | ||||
66As | ||||
67As | ||||
68As | ||||
69As | ||||
70As | ||||
71As | ||||
72As | ||||
73As | ||||
74As | ||||
75As | 100% | Stable | N/A | |
76As | ||||
77As | ||||
78As | ||||
79As | ||||
80As | ||||
81As | ||||
82As | ||||
83As | ||||
84As | ||||
85As | ||||
86As | ||||
87As | ||||
88As | ||||
89As | ||||
90As | ||||
91As | ||||
92As |
CAS Number | CAS7440-38-2 |
RTECS Number | {N/A, RTECSCG0525000, N/A} |
DOT Hazard Class | {N/A, 6.1, N/A} |
DOT Numbers | "N/A", {1558}, "N/A" |
EU Number | {N/A, N/A, N/A} |
NFPA Fire Rating | {N/A, 2, N/A} |
NFPA Hazards | N/ A, N/ A, N/ A |
NFPA Health Rating | {N/A, 3, N/A} |
NFPA Reactivity Rating | {N/A, N/A, N/A} |
Autoignition Point | N/A |
Flashpoint | N/A |
List of unique identifiers to search the element in various chemical registry databases
Database | Identifier number |
---|---|
CAS Number - Chemical Abstracts Service (CAS) | CAS7440-38-2 |
CID Number | {CID5359596, CID5359596, CID139279} |
Gmelin Number | {N/A, N/A, N/A} |
NSC Number | {N/A, N/A, N/A} |
RTECS Number | {N/A, RTECSCG0525000, N/A} |
Metalloid |
Nonmetals |
Other Nonmetals | |
Halogens | Noble Gas |
Metals |
|
Alkali Metals | Alkaline Earth Metals |
Transition Metals | Post-Transition Metals |
Lanthanide | Actinide |