Arsenic is the poisonous metalloid with the atomic number 33. Its name means yellow pigment. It was first discovered by Albertus Magnus in 1250. It is solid at room temperature. It is found in three different forms. The most common form is grey arsenic. It is soft and waxy. Last but not least is black arsenic. Arsenic is often found in silver ore veins. In murders, arsenic is usually the poison of choice. Although it is a poison, arsenic was once used as a medicine. It is commonly used in insect repellant and poisons. Its melting point is 817oC or 1503oF.


January 12, 2010