Quick Facts
| Property | Value |
|---|---|
| Symbol | Pb |
| Atomic Number | 82 |
| Atomic Mass | 207.2 u |
| Category | Post-Transition Metal |
| Period | 6 |
| Group | 14 |
| Block | p |
| Electron Configuration | [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p² |
Physical Properties
| Property | Value |
|---|---|
| State at 20°C | Solid |
| Density | 11.34 g/cm³ |
| Melting Point | 327.46°C (600.61 K) |
| Boiling Point | 1749°C (2022 K) |
| Appearance | Bluish-white, soft, dense metal |
History and Discovery
Discovered by: Known since antiquity Year of Discovery: ~7000 BCE Location: Various ancient civilizations
Etymology
Symbol "Pb" from Latin "plumbum" (hence "plumbing").
Applications and Uses
- Lead-acid batteries (main use—80%)
- Radiation shielding
- Ammunition
- Weights and ballast
- Historically: pipes, paint, gasoline (now banned)
Toxicity
Lead is a cumulative poison affecting the brain, nervous system, and blood. Childhood lead exposure causes permanent cognitive damage.
Interesting Facts
- Romans used lead pipes (plumbing comes from "plumbum")
- Lead was removed from gasoline and paint in the 1970s-80s
- Still used in car batteries worldwide
- Excellent radiation shield for X-rays
- Lead poisoning may have contributed to Rome's decline