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82
Pb
207.2
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Nasa: A cargo tag made of lead was unearthed during excavation of the original colony at Jamestown, Virginia. It is believed to have made the trip from England in 1611.
| Classification: | Lead is a metal |
| Atomic weight: | 207.2 g/mol |
| Density @ 20 oC: | 11.34 g/cm3 |
| Atomic volume: | 18.17 cm3/mol |
Discovery of Lead
Lead has been known since ancient times. Its ores are widely distributed and it has a low melting point so it is easily smelted.
It was used in antiquity to make statues, coins, utensils and writing tablets. The Romans also used lead for plumbing.
The Romans called lead 'plumbum nigrum' meaning black lead to differentiate it from 'plumbum album' meaning white lead. We now call 'white lead' tin. Tin sits directly above lead in the periodic table.
Lead's chemical symbol is Pb, which comes from its Latin name.
States
State (s, l, g): solid
Melting point: 600.61 K (327.46 oC)
Melting point: 600.61 K (327.46 oC)
Boiling point: 2023 K (1750 oC)
Energies
Specific heat capacity: 0.13 J g-1 K-1
Heat of fusion: 4.77 kJ mol-1
1st ionization energy: 715.6 kJ mol-1
3rd ionization energy: 3081.5 kJ mol-1
Heat of fusion: 4.77 kJ mol-1
1st ionization energy: 715.6 kJ mol-1
3rd ionization energy: 3081.5 kJ mol-1
Heat of atomization: 196 kJ mol-1
Heat of vaporization: 177.9 kJ mol-1
2nd ionization energy: 1450.5 kJ mol-1
Electron affinity: 35.1 kJ mol-1
Heat of vaporization: 177.9 kJ mol-1
2nd ionization energy: 1450.5 kJ mol-1
Electron affinity: 35.1 kJ mol-1
Oxidation & Electrons
Shells: 2,8,18,32,18,4
Minimum oxidation number: -4
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 2.33
Minimum oxidation number: -4
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 2.33
Electron configuration: [Xe] 4f14 5d10 6s2 6p2
Maximum oxidation number: 4
Max. common oxidation no.: 4
Polarizability volume: 6.8 Å3
Maximum oxidation number: 4
Max. common oxidation no.: 4
Polarizability volume: 6.8 Å3
Appearance & Characteristics
Structure: fcc: face-centered cubic
Hardness: 1.5 mohs
Hardness: 1.5 mohs
Uses of lead in the modern world.
The properties of lead explained.
Color: bluish gray
Harmful effects:
Lead and its compounds are poisonous.
Characteristics:
Lead is a bluish-gray, soft, dense metal that has a bright luster when freshly cut.
It tarnishes slowly in moist air to form a dull gray coating.
The metal is highly ductile and malleable.
Lead is extremely resistant to corrosion and is a poor conductor of electricity.
Uses:
Large quantities of lead, both as the metal and as the dioxide, are used in storage batteries.
Lead is also used in cable covering, as ammunition, as electrodes, in solder and as roofing material.
The metal is used as shielding from radiation, e.g. in x-ray rooms.and nuclear reactors.
Lead oxide is also used in the manufacture of fine crystal glass.
Historically, lead was used in plumbing.
Tetraethyl lead was used as an anti-knock agent in petrol, and as an additive in paints. These uses have been reduced recently because of environmental concerns about cumulative lead poisoning.
Harmful effects:
Lead and its compounds are poisonous.
Characteristics:
Lead is a bluish-gray, soft, dense metal that has a bright luster when freshly cut.
It tarnishes slowly in moist air to form a dull gray coating.
The metal is highly ductile and malleable.
Lead is extremely resistant to corrosion and is a poor conductor of electricity.
Uses:
Large quantities of lead, both as the metal and as the dioxide, are used in storage batteries.
Lead is also used in cable covering, as ammunition, as electrodes, in solder and as roofing material.
The metal is used as shielding from radiation, e.g. in x-ray rooms.and nuclear reactors.
Lead oxide is also used in the manufacture of fine crystal glass.
Historically, lead was used in plumbing.
Tetraethyl lead was used as an anti-knock agent in petrol, and as an additive in paints. These uses have been reduced recently because of environmental concerns about cumulative lead poisoning.
Reactions & Compounds
Reaction with air: mild, w/ht ⇒ PbO
Reaction with 15 M HNO3: mild, ⇒ NOx, Pb(NO3)2
Oxide(s): PbO (litharge), PbO2, Pb2O3, Pb3O4
Hydride(s): PbH4
Reaction with 15 M HNO3: mild, ⇒ NOx, Pb(NO3)2
Oxide(s): PbO (litharge), PbO2, Pb2O3, Pb3O4
Hydride(s): PbH4
Reaction with 6 M HCl: none
Reaction with 6 M NaOH:
Chloride(s): PbCl2 & PbCl4
Reaction with 6 M NaOH:
Chloride(s): PbCl2 & PbCl4
Radius
Atomic radius: 180 pm
Ionic radius (2+ ion): 133 pm
Ionic radius (2- ion): pm
Ionic radius (2+ ion): 133 pm
Ionic radius (2- ion): pm
Ionic radius (1+ ion): pm
Ionic radius (3+ ion): pm
Ionic radius (1- ion): pm
Ionic radius (3+ ion): pm
Ionic radius (1- ion): pm
Conductivity
Thermal conductivity: 35.3 W m-1 K-1
Electrical conductivity: 4.8 x 106 S m-1
Abundance & Isotopes
Abundance earth's crust: 14 parts per million by weight, 1 part per million by moles
Abundance solar system: 10 parts per billion by weight, 70 parts per trillion by moles
Cost, pure: $2.45 per 100g
Cost, bulk: $0.02 per 100g
Source: Lead rarely occurs naturally in nature and is can be found in ores, mainly with copper, zinc and silver. The principal lead mineral is lead sulfide (galena, PbS). Other common minerals are cerussite (lead carbonate, PbCO3) and anglesite (lead sulfate, PbSO4).
Lead is refined from galena (PbS) by heating. A large amount of lead is also recovered from recycling.
Isotopes: lead has 35 isotopes whose half-lives are known, mass numbers 181 to 215. Of these, only three are stable: 206Pb, 207Pb and 208Pb
Abundance solar system: 10 parts per billion by weight, 70 parts per trillion by moles
Cost, pure: $2.45 per 100g
Cost, bulk: $0.02 per 100g
Source: Lead rarely occurs naturally in nature and is can be found in ores, mainly with copper, zinc and silver. The principal lead mineral is lead sulfide (galena, PbS). Other common minerals are cerussite (lead carbonate, PbCO3) and anglesite (lead sulfate, PbSO4).
Lead is refined from galena (PbS) by heating. A large amount of lead is also recovered from recycling.
Isotopes: lead has 35 isotopes whose half-lives are known, mass numbers 181 to 215. Of these, only three are stable: 206Pb, 207Pb and 208Pb
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