Lead is soft and malleable, and has a relatively low melting point.
It is particularly problematic in children: even if blood levels are promptly normalized with treatment, permanent brain damage may result. The sum of lead's first and second ionization energies—the total energy required to remove the two 6p electrons—is close to that of tin, lead's upper neighbor in the carbon group.
This is unusual; ionization energies generally fall going down a group, as an element's outer electrons become more distant from the nucleus, and more shielded by smaller orbitals.
Lead is a chemical element with symbol Pb (from the Latin plumbum) and atomic number 82.
It is a heavy metal that is denser than most common materials.
Uranium–lead dating and lead–lead dating on this meteorite allowed refinement of the age of the Earth to 4.55 billion ± 70 million years.
Apart from the stable isotopes, which make up almost all lead that exists naturally, there are trace quantities of a few radioactive isotopes.
Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases, and it tends to form covalent bonds.
Compounds of lead are usually found in the 2 oxidation state rather than the 4 state common with lighter members of the carbon group.
Characteristic properties of lead include high density, malleability, and high resistance to corrosion (due to passivation).
Lead's tensile strength, at 12–17 MPa, is low (that of aluminium is 6 times higher, copper 10 times, and mild steel 15 times higher); it can be strengthened by adding small amounts of copper or antimony. The electrical resistivity of lead at 20 °C is 192 nanoohm-meters, almost an order of magnitude higher than those of other industrial metals (copper at 15.43 nΩ·m; gold 20.51 nΩ·m; and aluminium at 24.15 nΩ·m).
Lead has the highest atomic number of any stable element and concludes three major decay chains of heavier elements.