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:
“If you would be a leader of men you must lead your own generation, not the next. Your playing must be good now, while the play is on the boards and the audience in the seats.... It will not get you the repute of a good actor to have excellencies discovered in you afterwards.”
—Woodrow Wilson (1856–1924)
“We have been educated to such a fine—or dull—point that we are incapable of enjoying something new, something different, until we are first told what it’s all about. We don’t trust our five senses; we rely on our critics and educators, all of whom are failures in the realm of creation. In short, the blind lead the blind. It’s the democratic way.”
—Henry Miller (1891–1980)
“Many will come in my name and say, I am he!’ and they will lead many astray.”
—Bible: New Testament, Mark 13:6.