Arsenic (As)

Arsenic is a chemical element of the periodic table with chemical symbol As and atomic number 33 with an atomic weight of 74.9216 u and is classed as metalloid and is part of group 15 (nitrogen group). Arsenic is solid at room temperature.

Germanium Periodic table Selenium

Arsenic in the periodic table

Symbol	As
Atomic number	33
Group	15 (Nitrogen group)
Period	4
Block	p
Classification	Metalloid

Appearance	Metallic grey
Color	Silver

Number of protons	33 p⁺
Number of neutrons	42 n⁰
Number of electrons	33 e^-

From Wikipedia, the free encyclopediaArsenic 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.

Physical properties

Phase at STP	Solid
Density	5.727 g/cm³
Atomic weight	74.9216 u

Thermal properties

Melting point	-
Boiling point	-
Heat of vaporization	32.4 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)	2.18
Electron affinity	77.65 kJ/mol
Oxidation states	−3, −2, −1, 0, +1, +2, +3, +4, +5 (a mildly acidic oxide)
Ionization energies	947 kJ/mol 1798 kJ/mol 2735 kJ/mol 4837 kJ/mol 6043 kJ/mol 12310 kJ/mol

Electron configuration for arsenic

Electron configuration

Shorthand configuration

[Ar] 3d¹⁰ 4s² 4p³

Electron configuration

Full configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p³

Electron configuration chart

1s²
2s²	2p⁶
3s²	3p⁶	3d¹⁰
4s²	4p³

Electrons per shell

2, 8, 18, 5

Valence electrons

5

Valency electrons

5,3

Bohr model

Figure: Shell diagram of Arsenic (As) atom.

Orbital Diagram

1s
2s	2p
3s	3p	3d
4s	4p

The history of Arsenic

Discovery

Middle-Eastern alchemists (815)

Discovery of arsenic

During the Bronze Age, arsenic was often included in bronze, which made the alloy harder (so-called "arsenical bronze"). The isolation of arsenic was described by Muslim alchemist Jabir ibn Hayyan before 815 AD. Albertus Magnus (Albert the Great, 1193–1280) later isolated the element from a compound in 1250, by heating soap together with arsenic trisulfide. In 1649, Johann Schröder published two ways of preparing arsenic. Crystals of elemental (native) arsenic are found in nature, although rare.

Periodic table history

Identifiers

List of unique identifiers for Arsenic in various chemical registry databases

CAS Number	7440-38-2
ChemSpider ID	4514330
EC number	231-148-6
PubChem CID Number	5359596