Lead

Lead is a heavy, soft grey metal that was central to the Roman empire's water supply, and may have helped cause its decline. It poisons the nervous system, accumulating in bones. Yet it is still in wide use today: as the heavy plates in car batteries and as radiation shielding in hospitals and nuclear facilities.

  • Atomic Number8282 protons, 82 electrons
  • Atomic Mass207 u82× heavier than hydrogen
  • State at Room TempSolidSolid
  • Density11.342 g/cm³
  • Melting / Boiling327.5°C / 1748.8°C
  • DiscoveredAncient

What is Lead?

Lead has 82 protons and is the heaviest stable element. Its symbol Pb comes from the Latin plumbum, the root of the English word "plumber", Roman plumbers made pipes from lead. Lead melts at a low 327°C and is soft, dense and corrosion-resistant in most environments.

Known since antiquity. Symbol Pb from Latin plumbum. Used in Roman water pipes, paint and wine vessels. Recognised as an element by Lavoisier in 1789.

Fact The Roman empire piped water through lead (plumbum) pipes. Some historians argue this contributed to widespread lead poisoning in the Roman aristocracy, affecting cognition and perhaps contributing to Rome's eventual decline. Modern analysis of Roman bones and ice cores from the Alps showing elevated lead levels during the Roman period supports widespread contamination.

Where you find Lead

On Earth

Galena (PbS) is the main ore. Australia, China, Peru, Mexico and the USA are major producers.

How we use Lead

  • Lead-acid batteries.. Every petrol and diesel car contains a lead-acid battery (approx. 12 kg of lead) to start the engine and power lights. Around 85% of all lead goes into batteries.
  • Radiation shielding.. Lead blocks X-rays and gamma rays effectively and cheaply. Dentists' lead aprons, hospital walls, and nuclear facility shielding use lead.
  • Ammunition.. Lead shot and bullets are still widely used, though increasingly replaced by non-toxic alternatives to prevent wildlife poisoning.

How it was discovered

Known since antiquity. Symbol Pb from Latin plumbum. Used in Roman water pipes, paint and wine vessels. Recognised as an element by Lavoisier in 1789.

Deeper dive: lead properties

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Moving to 83 protons on the periodic table takes us to the next element.