![]() It damages the nervous system and interferes with the function of biological enzymes, causing neurological disorders ranging from behavioral problems to brain damage, and also affects general health, cardiovascular, and renal systems. Lead is a devastating and persistent neurotoxin that accumulates in soft tissues and bones. 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. In 2014, the annual global production of lead was about ten million tonnes, over half of which was from recycling. Lead played a crucial role in the development of the printing press, as movable type could be relatively easily cast from lead alloys. 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. Unfortunately, there was a slightly different system in place in Europe.Lead is a chemical element it has symbol Pb (from Latin plumbum) and atomic number 82. The first two groups are 1A and 2A, while the last six groups are 3A through 8A. The traditional system used in the United States involves the use of the letters A and B. There are two different numbering systems that are commonly used to designate groups, and you should be familiar with both. These two rows are pulled out in order to make the table itself fit more easily onto a single page.Ī group is a vertical column of the periodic table, based on the organization of the outer shell electrons. Periods 6 and 7 have 32 elements, because the two bottom rows that are separate from the rest of the table belong to those periods. Period 1 has only two elements (hydrogen and helium), while periods 2 and 3 have 8 elements. A new period begins when a new principal energy level begins filling with electrons. There are seven periods in the periodic table, with each one beginning at the far left. ![]() ![]() \) (Credit: User:Cepheus/Wikimedia Commons Source: (opens in new window) License: Public Domain)Ī period is a horizontal row of the periodic table. ![]()
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |