The similarity of ionization energies is caused by the lanthanide contraction—the decrease in element radii from lanthanum (atomic number 57) to lutetium (71), and the relatively small radii of the elements from hafnium (72) onwards.
Lead is a relatively unreactive post-transition metal.
Lead's high density, low melting point, ductility and relative inertness to oxidation make it useful.
These properties, combined with its relative abundance and low cost, resulted in its extensive use in construction, plumbing, batteries, bullets and shot, weights, solders, pewters, fusible alloys, white paints, leaded gasoline, and radiation shielding.
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.