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82Pb207.2

Element 82, a post-transition metal

Lead

A dense, soft metal used since ancient Rome, which gave us the word plumber, and a poison that harms children's brains.

At a glance

Symbol
Pb
Atomic number
82
Average atomic mass
207.2
Group
14
Period
6
Family
post-transition metal
Electron configuration
[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p²
Valence electrons
4
Electronegativity
2.33
Common ions
Pb²⁺, and +4 in a few compounds such as PbO₂

On the table

Periodic table with Lead highlighted123456789101112131415161718123456757-7189-103HHeLiBeBCNOFNeNaMgAlSiPSClArKCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKrRbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXeCsBaLaCePrNdPmSmEuGdTbDyHoErTmYbLuHfTaWReOsIrPtAuHgTlPbBiPoAtRnFrRaAcThPaUNpPuAmCmBkCfEsFmMdNoLrRfDbSgBhHsMtDsRgCnNhFlMcLvTsOg

Period 6, group 14. The other post-transition metals are tinted, and every cell opens its own article.

Electrons and bonding

Pb

Four valence electrons, but lead usually gives up only its two 6p electrons to form Pb²⁺, while its two 6s electrons hold on. Chemists call this the inert pair effect.

Properties

State at 25 °C
solid
What it looks like
soft, dense, bluish-gray metal
Melting point
327.5 °C
Boiling point
1749 °C
Density
11.3 g/cm³

Where it is found

Mined mostly as galena (PbS) in China, Australia, Peru and the United States, though more lead now comes from recycled batteries than from mines. It is the stable end point of the decay of uranium and thorium.

Discovery and name

Known since ancient times; the Romans used it for water pipes, cooking pots and coins. The name is Old English, and the symbol Pb comes from its Latin name plumbum, the source of the word plumber.

What it is used for

Lead-acid batteries for cars, trucks and backup power use about 80% of it. Lead also shields against X-rays and radiation and goes into ammunition, weights and roofing. It was once used widely in gasoline, paint, solder and water pipes, uses that are now banned or restricted.

In compounds

PbSgalenaPbO₂lead(IV) oxide, in car batteriesPbSO₄lead(II) sulfatePb(C₂H₅)₄tetraethyl lead, the old gasoline additivePbCrO₄lead chromate, chrome yellow

Handle with care

A cumulative poison that damages the brain and nervous system, especially in children, even at low levels. Lead leaching from old water pipes caused the Flint water crisis in Michigan in 2014.