LEAD ORE
Lead, atomic number 82 in the periodic table, is a metallic element with the chemical symbol Pb, which stands for plumbum, the Latin name for the element. It is a soft, pliable metal that is silvery-white in color when freshly cut, but on exposure to air quickly acquires a dull gray appearance due to the formation of a layer of oxide. Although occasionally found in its elemental state, the main lead ore is galena, or lead sulphide (PbS); other lead ores include cerussite — lead carbonate (PbCO3) — and anglesite — lead sulfate (PbSO4). Historically, the chemical and physical properties of lead have made it a very useful element, but since the late 20th century, its use has diminished due to its toxicity. Lead, however, still has a number of important applications — for example in lead-acid batteries, for radiation shielding, and as a flexible, resilient roofing material.
The metal melts at 622.4 °F (328 °C) and boils at 3,164 °F (1,740 °C). The four stable isotopes of lead are the end products of the decay of various naturally occurring radioactive elements, such as uranium and thorium, through a number of steps. Lead is the heaviest stable element, a distinction that used to belong to bismuth — element number 83 — until it was found to be very slightly radioactive. One of the most important physical properties of lead is its ability to absorb high frequency electromagnetic radiation, such as x-rays and gamma rays. This is due to its high density and the large number of electrons in the lead atom.
The metal melts at 622.4 °F (328 °C) and boils at 3,164 °F (1,740 °C). The four stable isotopes of lead are the end products of the decay of various naturally occurring radioactive elements, such as uranium and thorium, through a number of steps. Lead is the heaviest stable element, a distinction that used to belong to bismuth — element number 83 — until it was found to be very slightly radioactive. One of the most important physical properties of lead is its ability to absorb high frequency electromagnetic radiation, such as x-rays and gamma rays. This is due to its high density and the large number of electrons in the lead atom.
