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Lead [Pb] locate me
CAS-ID: 7439-92-1
An: 82 N: 125
Am: 207.2 (1) g/mol
Group No: 14
Group Name: Metals
Block: p-block  Period: 6
State: solid at 298 K
Colour: bluish white Classification: Metallic
Boiling Point: 2022K (1749°C)
Melting Point: 600.61K (327.46°C)
Superconducting temperature: 7.2K (-265.9°C)
Density: 11.34g/cm3
Availability: Lead is available in several forms including foil, granules, ingots, powder, rod, shot, sheet, and wire.
Discovery Information
Who: Known to the ancients. Lead has been used by humans for at least 7000 years, because it is widespread, easy to extract and easy to work with.
Name Origin
Latin: plumbum.
 "Lead" in different languages.
Sources
Lead occurs rarely in nature. The main lead mineral is galena (lead sulfide, PbS) (which is 86.6% lead). Lead is also found in ore with zinc, silver and (most abundantly) copper.
Primary producers are the USA, Australia, Mexico, Germany and France. Annual production is around 2.8 million tons.
Abundance
 Universe: 0.01 ppm (by weight)
 Sun: 0.01 ppm (by weight)
 Carbonaceous meteorite: 1.4 ppm
 Earth's Crust: 14 ppm
 Seawater:
   Atlantic surface: 3 x 10-5 ppm
   Atlantic deep: 4 x 10-6 ppm
   Pacific surface: 1 x 10-5 ppm
   Pacific deep: 1 x 10-6 ppm
 Human:
   1700 ppb by weight
   50 ppb by atoms
Uses
Used in solder, as a colouring agent in ceramic glazes (red and yellow), shielding against radiation, roofing, in (lead-acid) batteries and ammunition.
Lead is used in some candles to treat the wick to ensure a longer, more even burn. Because of the dangers, European and North American manufacturers use more expensive alternatives such as zinc.
History
Lead has been used by humans for at least 7000 years, because it is widespread, easy to extract and easy to work with. It is highly malleable and ductile as well as easy to smelt. In the early Bronze Age lead was used with antimony and arsenic. Alchemists thought that lead was the oldest metal and associated it with the planet Saturn. Lead pipes that bear the insignia of Roman emperors are still in service and many Roman "pigs" (ingots) of lead figure in Derbyshire lead mining history and in the history of the industry in other English centres. Lead's symbol Pb is an abbreviation of its Latin name plumbum for soft metals; originally it was plumbum nigrum, where plumbum candidum was tin. The English word "plumbing" also derives from this Latin root.
Lead is also very toxic, and lead poisoning was recognized even by the ancients. Similarly, in the Twentieth Century, the use of lead in paint pigments was ended because of the danger of lead poisoning, especially to children. By the mid-1980s, a significant shift in lead end-use patterns had taken place. Much of this shift was a result of the U.S. lead consumers' compliance with environmental regulations that significantly reduced or eliminated the use of lead in nonbattery products, including gasoline, paints, solders, and water systems. Recently, lead use is being further curtailed by the European Union's RoHS directive. Lead may still be found in harmful quantities in stoneware, vinyl (such as that used for tubing and the insulation of electrical cords), and brass manufactured in China.
History
Lead has been used by humans for at least 7000 years, because it is widespread, easy to extract and easy to work with. It is highly malleable and ductile as well as easy to smelt. In the early Bronze Age lead was used with antimony and arsenic.
Lead pipes that bear the insignia of Roman emperors are still in service and many Roman "pigs" (ingots) of lead figure in Derbyshire lead mining history and in the history of the industry in other English centres.
Notes
Lead can be toughened by adding a small amount of antimony or other metals to it.
Hazards
Lead is extremely toxic, but its effects are accumulative and most often develop after extended exposure. Lead affects the nervous system, causing mental retardation or other nervous disorders. It also affects other organs of the body. People suffering from lead poisoning may exhibit weakness, general disability, nervous disorders and eventual death. Children are most susceptible, partly because they have rapid metabolism and are small and partly because of their habits. They chew on things that might contain lead paint and play on floors and ground that might be contaminated, often putting their fingers in their mouth.
Lead is a poisonous metal that can damage nervous connections and cause blood and brain disorders. A classic example of lead poisoning occurred in the early 1900's, but the cause of death was only recently determined. A large number of explorer families traveled to Alaska. The guide who escorted them contacted many different suppliers for provisions. He got a really good deal on canned food that he couldn't refuse. They set out on their journey and were never heard from again. Searchers never found any survivors. Years later someone decided to find out what happened. Bodies were found along with provisions. As it turned out, the cans had been sealed with lead solder. All of the human remains were very high in lead content. They had, in fact, all died of lead poisoning.
In the Twentieth Century, the use of lead in paint pigments was ended because of the danger of lead poisoning, especially to children.