Lead is a devastating and persistent neurotoxin that accumulates in soft tissues and bones. Lead played a crucial role in the development of the printing press, as movable type could be relatively easily cast from lead alloys. These properties, combined with its relative abundance and low cost, resulted in its extensive use in construction, plumbing, batteries, bullets and shot, weights, solders, pewters, fusible alloys, white paints, leaded gasoline, and radiation shielding. Lead's high density, low melting point, ductility and relative inertness to oxidation make it useful. Lead production declined after the fall of Rome and did not reach comparable levels until the Industrial Revolution. Interest in silver helped initiate widespread extraction and use of lead in ancient Rome. Galena is a principal ore of lead which often bears silver. Since lead is easily extracted from its ores, prehistoric people in the Near East were aware of it. Like the lighter members of the group, lead tends to bond with itself it can form chains and polyhedral structures. Exceptions are mostly limited to organolead compounds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Its weak metallic character is illustrated by its amphoteric nature lead and lead oxides react with acids and bases, and it tends to form covalent bonds. Lead is a relatively unreactive post-transition metal. Lead is toxic, even in small amounts, especially to children. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. It tarnishes to a dull gray color when exposed to air. When freshly cut, lead is a shiny gray with a hint of blue. Lead is soft and malleable, and also has a relatively low melting point. It is a heavy metal that is denser than most common materials. Lead is a chemical element with the symbol Pb (from the Latin plumbum) and atomic number 82.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |