Lead 2 revised for chem (temporary)

LEAD

Presented by : Jomz Soliveres

Lead

It is a chemical element in the carbon group with its symbol Pb (derived from the Latin name – Plumbum)

Its atomic number is 82 Its atomic mass is 207.2 Its melting point is 327.5 celcius It is a soft and malleable metal with may be

regarded as a heavy and poor metal.

Continuation ... Lead

Metallic leads are bluish-white color after being freshly cut

Later it turns to a dull greyish color when exposed to the atmosphere.

Lead has a characteristic of being a shiny chrome-silver luster whenever it is being melted into liquid.

Lead has the highest atomic number of all the stable elements in the periodic table.

Lead...

Lead has a certain degrees, although poisonous susbtance to animals sometimes including the humans.

It can destroy the humans' nervous system, or even brain disorders. Excessive lead may cause blood disorders to mammals.

Lead is also a neurotoxin that accumulates both in soft tissues and bones

Lead poisoning had been reported to certain countries like ancient Rome, Greece, China.

Uses of Lead

Lead's uses are building construction, lead-acid batteries, bullets and shot, weights, pewters, fusible alloys, and a radiation shield.

Characteristics of Lead

Lead is a bright and silvery metal with a very slight shade of blue in a dry atmosphere.

With the contact of air, it begins to tarnish by forming a complex mixture of compounds depending on the condition around it.

Its few properties are: high density, softness, ductility, malleability, poor electrical conductivity compared to other metals, high resistance of corrosion, and ability to react with organic chemicals.

Chemical Reactivity

Lead is classified as a post-transposition metal and is also part of the carbon group.

Lead only forms a protective oxide layer although finely powdered highly purified can ignite in the air.

Melted lead is oxidize in the air to lead monoxide.

History

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Lead has been commonly used for thousands of years because it is widespread, easy to extract and easy to work with. It is highly malleable as well as easy to smelt. Metallic lead beads dating back to 6400 BCE have been found in Çatalhöyük in modern-day Turkey. In the early Bronze Age, lead was used with antimony and arsenic.The largest preindustrial producer of lead was the Roman economy, with an estimated annual output of 80,000 tonnes, which was typically won as a by-product of extensive silver smelting. Roman mining activities occurred in Central Europe, Roman Britain, the Balkans, Greece, Asia Minor and Hispania which alone accounted for 40% of world production.

History...

Roman lead pipes often bore the insignia of Roman emperors. Lead plumbing in the Latin West may have been continued beyond the age of Theoderic the Great into the medieval period. Many Roman "pigs" (ingots) of lead figure in Derbyshire lead mining history and in the history of the industry in other English centers. The Romans also used lead in molten form to secure iron pins that held together large limestone blocks in certain monumental buildings. In alchemy, lead was thought to be the oldest metal and was associated with the planet Saturn. Alchemists accordingly used Saturn's symbol (the scythe, ♄) to refer to lead.

History...

Up to the 17th century, tin was often not distinguished from lead: lead was called Plumbum nigrum (literally, "black lead"), while tin was called plumbum candidum (literally, "bright lead"). Their inherence through history can also be seen in other languages: the word "olovo" means lead in Czech, but in Russian it ("олово") means tin.Lead's symbol Pb is an abbreviation of its Latin name plumbum for soft metals; the English words "plumbing", "plumber", "plumb", and "plumb-bob" also derive from this Latin root.

History...end

Lead production in the US commenced as early as the late 1600s by Indians in the The Southeast Missouri Lead District, commonly called the Lead Belt, is a lead mining district in the southeastern part of Missouri. Significant among Missouri's lead mining concerns in the district was the Desloge Family and Desloge Consolidated Lead Company in Desloge, Missouri and Bonne Terre – having been active in lead trading, mining and lead smelting from 1823 in Potosi to 1929.

Health effects

Lead is a highly poisonous metal (regardless if inhaled or swallowed), affecting almost every organ and system in the body. The main target for lead toxicity is the nervous system, both in adults and children. Long-term exposure of adults can result in decreased performance in some tests that measure functions of the nervous system. Long-term exposure to lead or its salts (especially soluble salts or the strong oxidant PbO2) can cause nephropathy, and colic-like abdominal pains. It may also cause weakness in fingers, wrists, or ankles.

Health Effects

Lead exposure also causes small increases in blood pressure, particularly in middle-aged and older people and can cause anemia. Exposure to high lead levels can severely damage the brain and kidneys in adults or children and ultimately cause death. In pregnant women, high levels of exposure to lead may cause miscarriage. Chronic, high-level exposure have shown to reduce fertility in males.[ Lead also damages nervous connections (especially in young children) and cause blood and brain disorders. Lead poisoning typically results from ingestion of food or water contaminated with lead; but may also occur after accidental ingestion of contaminated soil, dust, or lead-based paint.

Health Effects

It is rapidly absorbed into the bloodstream and is believed to have adverse effects on the central nervous system, the cardiovascular system, kidneys, and the immune system. The component limit of lead is a test benchmark for pharmaceuticals, representing the maximum daily intake an individual should have. However, even at this low level, a prolonged intake can be hazardous to human beings. The treatment for lead poisoning consists of dimercaprol and succimer