Lead is a chemical element in the carbon group with symbol Pb (from Latin: plumbum) and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed to air. Lead has a shiny chrome-silver luster when it is melted into a liquid.
Lead is used in building construction, lead-acid batteries, bullets and shot, weights, as part of solders, pewters, fusible alloys, and as a radiation shield. Lead has the highest atomic number of all of the stable elements, although the next higher element, bismuth, has a half-life that is so long (much longer than the age of the universe) that it can be considered stable. Its four stable isotopes have 82 protons, a magic number in the nuclear shell model of atomic nuclei.
Lead, at certain contact degrees, is a poisonous substance to animals, including humans. It damages the nervous system and causes brain disorders. Excessive lead also causes blood disorders in mammals. Like the element mercury, another heavy metal, lead is a neurotoxin that accumulates both in soft tissues and the bones. Lead poisoning has been documented from ancient Rome, ancient Greece, and ancient China.
Read more about Lead: Characteristics, Compounds, History, Occurrence, Health Effects
Famous quotes containing the word lead:
“Those who follow where their genitals lead them often wind up in tedious company.”
—Mason Cooley (b. 1927)
“If this bureau had a prayer for use around horse parks, it would go something like this: Lead us not among bleeding-hearts to whom horses are cute or sweet or adorable, and deliver us from horse-lovers. Amen.... With that established, let’s talk about the death of Seabiscuit the other night. It isn’t mawkish to say, there was a racehorse, a horse that gave race fans as much pleasure as any that ever lived and one that will be remembered as long and as warmly.”
—Walter Wellesley (Red)
“The greatest, or rather the most prominent, part of this city was constructed with the design to offer the deadest resistance to leaden and iron missiles that might be cast against it. But it is a remarkable meteorological and psychological fact, that it is rarely known to rain lead with much violence, except on places so constructed.”
—Henry David Thoreau (1817–1862)