Lead Pb (Element 82) of Periodic Table

82 Pb (Lead)

Appearance:  Metallic gray

Standard Atomic weight:  207.2 g/mol

Mass number:  207

Atomic number (Z):  82

Electrons:  82

Protons:  82

Neutrons:  125

Group:  14

Period:  6

Block:  p

Element category:  Post-transition metal

Electrons per shell:  K2, L8, M18, N32, O18, P4

Electron configuration:  1s22s22p63s23p63d104s24p64d105s25p64f145d106s26p2

Phase:  Solid

Melting point:  600.61 K (327.46 oC)

Boiling point:  2022 K (1749 oC)

Density:  11.34 g/cm3 (In solid), 10.66 g/cm3 (When liquid at m.p)

Neutron cross section (Brans):  0.171

Heat of fusion:  4.77 kJ/mol

Heat of vaporization:  179.5 kJ/mol

Molar heat capacity:  26.650 J/(mol∙K)

Molar volume:  18.27×10-6 m3/mol

Oxidation states:  4, 3, 2, 1, -1, -2, -4

Ion charge:  Pb2+, Pb4+

Electronegativity:  pauling scale; 1.87

Valence:  4

Electro affinity:  35.1 kJ/mol

Ionization energies:  1st: 715.6 kJ/mol, 2nd: 1450.5 kJ/mol 3rd: 3081.5 kJ/mol

Atomic radius:  empirical: 175 pm

Covalent radius:  146±5 pm

Vander Waals radius:  202 pm

Crystal structure:  Face centered cubic

Grid parameters:  4.950 Å

Debye temperature:  88 K (-185.15 oC)

Sound speed:  1190 m/s

Thermal expansion:  28.9 μm/(m∙K)

Thermal conductivity:  35.3 W/(m∙K)

Electrical resistivity:  208 nΩ∙m

Magnetic ordering:  Diamagnetic

Magnetic susceptibility:  -23.0×10-6 cm3/mol

Volume magnetic susceptibility:  -0.000017

Mass magnetic susceptibility:  -1.5×10-9 m3/kg

Molar magnetic susceptibility:  -3.11×10-10

Superconducting point:  7.2 K (-265.95 oC)

Young’s modulus:  16 GPa

Shear modulus:  5.6 GPa

Bulk modulus:  46 GPa

Poisson ratio:  0.44

Mohs hardness:  1.5

Brinell hardness:  38-50 MPa

CAS Number:  7439-92-1

Discovery:  In the Middle East (7000 BCE)

Isotopes:  204Pb 206Pb 207Pb 208Pb

Lead Uses:  

It is used in car batteries, pigments, ammunition, cable sheathing, weights for lifting, weight belts for diving, lead crystal glass, radiation protection etc..

It is often used to store corrosive liquids and It is also sometimes used in architecture, for roofing and in stained glass windows.

Biological role of Lead: 

It can accumulate in the body and cause serious health problems. It is toxic, teratogenic and carcinogenic. Daily intake of lead from all sources is about 0.1 miligrams and the average human body stores approx 120 miligrams of lead in the bones.

Natural abundance of Lead:   

Lead is chiefly obtained from the mineral galena by a roasting process. At least 40% of lead in the UK is recycled from secondary sources such as scrap batteries and pipes.


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