33
As
74.9216
Arsenic
Metalloid
Group 15
Period 4
Block p
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.
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 |
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Electron configuration for arsenic
Electron configuration Shorthand configuration | [Ar] 3d10 4s2 4p3 | ||||||||||||||||||||||||||
| Full configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p3 | ||||||||||||||||||||||||||
Electron configuration chart |
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| 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 |
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The history of Arsenic
| Discovery | Zosimos of Panopolis (300) |
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. | |
| Original word | arsenikon |
| Language of origin | Greek |
| Name source | Mineral |
| Meaning | “Orpiment” |
Naming The name is thought to come from the Greek word 'arsenikon' meaning yellow orpiment or from the Greek word 'arsenikos' meaning strong, brave or male. Word was adopted in Latin as arsenicum, which in French became arsenic, from which the English word arsenic is taken. | |