Arsenic Arsenic Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the gray form, which has a metallic appearance, is important to industry. The primary use of arsenic is in alloys of lead (for example, in car batteries and ammunition). Arsenic is a common n-type dopant in semiconductor electronic devices, and the optoelectronic compound gallium arsenide is the second most commonly used semiconductor after doped silicon. Arsenic and its
Group 3 element upper neighbor of yttrium, which he called "eka-boron". Swedish chemist Lars Fredrik Nilson and his team discovered the missing element in the minerals euxenite and gadolinite and prepared 2 grams of scandium(III) oxide of high purity. He named it scandium, from the Latin "Scandia" meaning "Scandinavia". Chemical experiments on the element proved that Mendeleev's suggestions were correct; along with discovery and characterization of gallium and germanium this proved the correctness of the whole periodic table and periodic law. Nilson was apparently unaware of Mendeleev's prediction, but Per Teodor Cleve recognized the correspondence and notified Mendeleev. Metallic scandium was produced for