|Atomic Symbol||Atomic symbol::As|
|Atomic Number||Atomic number::33|
|Atomic Weight||Atomic weight::74.9 g/mol|
|Appearance|| metallic gray |
|Group, Period, Block||15, 4, p|
|Electron configuration||[Ar] 4s2 3d10 4p3|
|Electrons per shell|| 2, 8, 18, 5 |
|CAS number||CAS number::7440-38-2|
|Melting point||Melting point::1090K|
|Boiling point||Boiling point::subl. 887K|
|Isotopes of Arsenic|
|All properties are for STP unless otherwise stated.|
Arsenic is a chemical element known by the chemical symbol As, and bearing the atomic number of 33. It is a member of the metalloids, a group of elements including boron, silicon, and polonium. Arsenic has the atomic symbol As and an atomic weight of 74.9 g/mol. It is metallic gray in appearance. Arsenic is poisonous and can be fatal if ingested or exposed to for an extended length of time, as well as cause a variety of health issues such as cancer. Arsenic occurs as both a natural and a man-made substance, which can be used in medicine, insecticides, and the production of metals.
Arsenic can appear in three forms: stable, metallic, and nonmetallic. The stable form is a brittle crystalline solid. It is silver-gray in appearance and tarnishes rapidly when exposed to air. When exposed to high temperatures it burns and forms a white cloud of arsenic trioxide. The metallic form also oxidizes into arsenic trioxide when heated, and retains its brittle quality. The nonmetallic form, in comparison, is much less reactive. When heated with strong oxidizing acids and alkalis, however, this form dissolves. 
Naturally, arsenic can be found in the earth in small concentrations. Volcanoes exert three thousand tons of arsenic into the atmosphere every year and humans are responsible for even more; the burning of fossil fuels release eighty thousand tonnes of arsenic per year. Arsenic naturally occurs in soil and minerals. Wind and water run-off deposit this natural arsenic into air, water, and land. Due to arsenic's mobile nature, it is difficult to find large pockets of arsenic in one spot. It often spreads out when released. Because of arsenic's poisonous nature, its tendency to spread is beneficial to life.
Most of our arsenic is found with sulfur in minerals such as arsenopyrite, realgar, orpiment, and enargite, though no arsenic is mined as such. Instead, arsenic is produced by refining ores such as copper and lead, which release arsenic as a by-product. From copper and lead ores the world produces over ten million tonnes of arsenic. 
Despite its toxicity, humans have found many uses for arsenic. For years it has been applied in the manufacturing of copper, lead, and alpha-brass, which is used in plumbing. In coordination with other elements, arsenic is used in pigments, poison gasses, and insecticides,  though the use of it in herbicides, pesticides, and insecticides is dwindling due the banning of these products.
Arsenic has been used in medicine for many years. This element shows promise in cures for diseases such as cancer and psoriasis and can also be helpful in the location of tumors within the body because it provides a clearer picture than iodine. During the First World War and the Vietnam War, arsenic was used to create biological weapons. Along with lead, arsenic has been removed from the production of optical glass due to protests by environmentalists. 
Health Effects of Arsenic
Because of its dangerous properties, contact with arsenic can have many negative effects on the health of a living creature. Humans are exposed to arsenic mainly through food and water. Small traces of arsenic can be found in many types or animals, but are especially concentrated in seafood. Most arsenic found in food, however, is organic arsenic, which is thought to be less toxic than inorganic arsenic.
When an area is contaminated by arsenic its water sources are poisoned. This can occur naturally or through human means. Long-time exposure to contaminated drinking water may cause a variety of health effects, such as skin, lung, bladder, and kidney cancer. Thickening and pigmentation of the skin may also occur. In Taiwan a disease called blackfoot disease, which causes painful black pustules on the feet, is known to have occurred because of contaminated water sources.
Smokers inhale an average of ten times more arsenic per day than nonsmokers, though this may vary in more polluted areas. Inhalation of arsenic from smoking or exposure in the workplace may cause lung cancer. Ingestion of large amounts of arsenic can lead to symptoms such as severe vomiting, damage to the nervous system, disturbances of the blood and circulation, and even death. 
- Author Unknown. Arsenic - As. "Lenntech". Accessed December 23, 2012.
- Author Unknown. Uses of Arsenic Weitz & Luxenburg. Web. Accessed December 11, 2012.
- Unknown Author. Uses of Arsenic. Want To Know It?. Web. Accessed December 23, 2012.
- Author Unknown. Arsenic. "Green Facts". Accessed December 27, 2012.