Lead (pronounce: "/'lɛd/") is achemical element. Itschemical symbol isPb, which comes fromplumbum, theLatin word for lead.[6] Itsatomic number is 82,atomic mass is 207.2 and has a melting point of 327.8°C. It is a verypoisonous and heavymetal, and is also the ending element to thestable elements, although the next element, bismuth, is so weakly radioactive that it can be considered stable for practical purposes.[7]
Lead is a shiny, gray-bluepoor metal. It getstarnished easily to a dull gray color. It is soft andmalleable. It is very shiny when it is melted. It is very heavy. It is verycorrosion-resistant. It is made stronger by addingantimony orcalcium. It can form an alloy withsodium. It is toxic to people and animals when swallowed.
Lead makeschemical compounds in two mainoxidation states: +2 and +4. +2 compounds, also known as lead(II) compounds or plumbous compounds, are weakoxidizing agents. +4 compounds, also known as lead(IV) compounds or plumbic compounds, are strong oxidizing agents. Lead compounds are toxic just like the element. The leadhalides do not dissolve in water.Lead(IV) oxide is the most common lead(IV) compound. It is a black solid. The lead oxides are all colored, while the other salts are white or colorless.Lead nitrate andlead(II) acetate are thesoluble compounds of lead.
+2 compounds
This state is more common than the +4 state. These are weakoxidizing agents. All but the oxides are colorless or white.
Lead was used for thousands of years because it is easy to get from the ground and easy to shape and work with. The Romans used lead very commonly. They used it for pipes, drinking vessels, andfasteners.
Lead is made from galena. Galena is made pure byfroth flotation to get all the impurities out. Then the lead sulfide is roasted in a furnace to makelead(II) oxide. The lead(II) oxide is heated withcoke to make liquid lead metal.
The dark bricks are made of lead. They are meant to keep people safe from the radioactive material inside.
Lead is used in theballast ofsailboats. It is also used in weight belts forscuba diving. It is also used to makeshotgun pellets andbullets forsmall arms. Someprinting presses use lead type because it can be easily shaped. It can be used outside because it does not corrode in water.
Most lead is used inlead acid batteries, though. The lead isoxidized, makingelectricity. Sheets of lead are used to block sound in some places. Lead is used in radiation shielding. Molten lead can be used as acoolant innuclear reactors. It used to be mixed withtin to make the pipes inpipe organs. Different amounts of lead make different sounds. In addition, lead has found its usage insolder.
It is used in some solder. It is used in covering for wires that carry high voltage. Sometennis rackets have lead in them to make them heavier. It is used to balance wheels of cars, to make statues, and to make decorative looks in buildings.
Many lead compounds are used to make coloredglazes inceramics. Lead can be used inPVC pipes. Lead compounds are added tocandles to make them burn better.Lead glass has lead(II) oxide in it. Lead compounds are still used aspigments in some places. Lead compounds were added to gasoline, but are now outlawed. Some lead compounds aresemiconductors and are used inphotodetectors.
Lead was used in many red, yellow, and white pigments in paints. Lead was also used inpesticides. Lead used to be used in pipes carrying water, but now it is not because lead can leach into the water.
Although it can be safely touched, exposure to lead should be avoided – it is verytoxic to humans and otheranimals when swallowed, and its use is restricted in manycountries.
If someone is exposed to lead for a long time, it ruins theirkidneys and gives themabdominal pains. Lead also ruins thenervous system. Lead paint was being eaten by children and they were gettinglead poisoning.
The best way to understand lead and its properties is to read itsMSDS.
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