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Lead Facts

Chemical & Physical Properties

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Lead is a heavy metal that is bluish-white when freshly cut, but tarnishes to a dull gray.

Lead is a heavy metal that is bluish-white when freshly cut, but tarnishes to a dull gray upon exposure to air. The pure metal is used for radioactive shielding, among other purposes.

L. Chang, wikipedia.org
Periodic Table of the Elements

Lead

Symbol: Pb

Atomic Number: 82

Atomic Weight: 207.2

Element Group: Basic Metal

Discovery: Known to the ancients, with a history dating back at least 7000 years. Mentioned in the book of Exodus.

Name Origin: Anglo-Saxon: lead; symbol from Latin: plumbum.

Density (g/cc): 11.35

Melting Point (°K): 600.65

Boiling Point (°K): 2013

Properties: Lead is an extremely soft, highly malleable and ductile, poor electrical conductor, resistant to corrosion, blue-white shiny metal that tarnishes to dull gray in air. Lead is the only metal in which there is zero Thomson effect. Lead is a cumulative poison.

Atomic Radius (pm): 175

Atomic Volume (cc/mol): 18.3

Covalent Radius (pm): 147

Ionic Radius: 84 (+4e) 120 (+2e)

Specific Heat (@20°C J/g mol): 0.159

Fusion Heat (kJ/mol): 4.77

Evaporation Heat (kJ/mol): 177.8

Debye Temperature (°K): 88.00

Pauling Negativity Number: 1.8

First Ionizing Energy (kJ/mol): 715.2

Oxidation States: 4, 2

Electronic Configuration: [Xe] 4f145d106s26p2

Lattice Structure: Face-Centered Cubic (FCC)

Lattice Constant (Å): 4.950

Isotopes: Natural lead is a mixture of four stable isotopes: 204Pb (1.48%), 206Pb (23.6%), 207Pb (22.6%), and 208Pb (52.3%). Twenty-seven other isotopes are known, all radioactive.

Uses: Lead is used as a sound absorber, x radiation shield, and to absorb vibrations. It is used in fishing weights, to coat the wicks of some candles, as a coolant (molten lead), as ballast, and for electrodes. Lead compounds are used in paints, insecticides, and storage batteries. The oxide is used to make leaded 'crystal' and flint glass. Alloys are used as solder, pewter, type metal, bullets, shot, antifriction lubricants, and plumbing.

Sources: Lead exists in its native form, though it is rare. Lead may be obtained from galena (PbS) by a roasting process. Other common lead minerals include anglesite, cerussite, and minim.

Other Facts: Alchemists believed lead to be the oldest metal. It was associated with the planet Saturn.

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952)

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