Lead

Description and Uses

Lead is the 82nd element of the periodic table. It has been used as a common, unreactive metal for thousands of years. However, we now know that lead is both poisonous and carcinogenic, so it has few uses in the modern world. In Roman times, it was known as “plumbum”, which is where its symbol “Pb” comes from.

Lead's main use was in pipes. The Romans used it to build large water pipes in cities across the empire. It was a cheap, easily malleable and long-lasting metal, so perfect for its job. Many Roman lead water pipes still exist now, though they are slowly being replaced, usually with plastic.

One of lead's uses now is as a store of corrosive materials, such as sulfuric acid in lead batteries. This is due to its unreactivity, as it does not react to the acid it stores.

Lead has 9 naturally occurring isotopes, with atomic weights ranging from 204 to 214. It has 4 observationally stable isotopes, being ²⁰⁴Pb, ²⁰⁶Pb, ²⁰⁷Pb, ²⁰⁸Pb, with ²⁰⁶Pb, ²⁰⁷Pb and ²⁰⁸Pb being at the end of the uranium, actinium and thorium decay series respectively. The most abundant lead isotope is ²⁰⁸Pb, with an abundance of around 52%. It is also the heaviest stable isotope. Lead has 6 radioactive isotopes, with ²¹⁴Pb having the shortest half-life, being just 26.8 minutes. ²¹⁰Pb and ²¹⁴Pb are parts of the uranium decay series; ²⁰⁷Pb and ²¹¹Pb are part of the actinium decay series; and ²⁰⁸Pb and ²¹²Pb are part of the thorium decay series. The remaining ²⁰⁹Pb occurs naturally as a part of the decay of ²³⁷Np.