Lead
post transition metalProperties
| Property | Value |
|---|---|
| Atomic Mass | 207.2 amu |
| Category | post transition metal |
| Group | 14 |
| Period | 6 |
| Electron Configuration | [Xe] 4f14 5d10 6s2 6p2 |
| Electronegativity | 1.87 (Pauling) |
| Oxidation States | 4, 2 |
| Melting Point | 600.61 K (327.5 °C) |
| Boiling Point | 2022 K (1748.8 °C) |
| Density | 11.34 g/cm³ |
About Lead
Lead is the metal humans have been smelting longest — beads from Çatalhöyük date to around 6500 BCE — and almost everything memorable about it traces back to the same set of properties: it melts at 327°C (low enough for a campfire), it is dense (11.34 g/cm³, close to gold), and it deforms instead of cracking. The Romans cast it into pipes for aqueducts, which is where the symbol Pb comes from (Latin plumbum) and where the word plumber comes with it. Lead's group-14 chemistry leans hard on the inert-pair effect: the 6s² electrons stay put, so Pb²⁺ is stable and Pb⁴⁺ is a strong oxidizer rather than the more common +4 state seen above it in the group. The same density that made it useful for shielding gamma rays made it catastrophic in gasoline — tetraethyl lead emissions raised blood lead levels in entire populations until phase-outs began in the 1970s. Today over 85% of refined lead goes into lead-acid batteries, and over 99% of those batteries are recycled, making Pb one of the most closed-loop metals in industry.
Fun Fact
The removal of lead from gasoline starting in the 1970s caused average blood lead levels in Americans to drop by 75 percent within a decade, and some researchers have linked this decline to the subsequent drop in violent crime rates.
Common Uses
- Lead-acid batteries for vehicles, forklifts, and backup UPS systems
- Gamma and X-ray shielding in medical and nuclear facilities
- Ammunition, fishing weights, and balance ballast
- Acid-resistant linings in sulfuric acid chambers and chemical plants
- Leaded solder for legacy electronics and stained glass