82Pb

Lead

Post-transition metalsolidblock p

The dense soft metal that plumbed Rome and shielded X-ray rooms, and whose isotopes were used to date the Earth at 4.55 billion years.

Atomic number	82
Standard atomic weight	207.2 g/mol ± 1.1
Group · period	14 · 6
Electron configuration	[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p²

About Lead

Lead's ±1.1 uncertainty is the largest of any element's atomic weight, and it is not a measurement problem: three of the four stable lead isotopes are the endpoints of the uranium and thorium decay chains, so a sample's isotopic mix depends entirely on the geological history of the ore it came from. Clair Patterson turned that into the age of the Earth in 1953, measuring lead isotopes in the Canyon Diablo meteorite to get 4.55 billion years — and then spent the rest of his career fighting the lead industry after his ultra-clean laboratories revealed how thoroughly tetraethyl lead had contaminated the modern world. The word plumbing comes from plumbum; the Romans piped water through it and sweetened wine with lead acetate, which was a very bad idea.

Use 207.2 g/mol in these solvers

Moles from Mass (n = m/M)

n = \frac{m}{M}

Opens with M = 207.2 g/mol already filled in

Gas Density from Molar Mass

\rho = \frac{PM}{RT}

Opens with M = 207.2 g/mol already filled in

Faraday's Law of Electrolysis (m = QM/nF)

m = \frac{Q M}{n F}

Opens with M = 207.2 g/mol already filled in

Ion Concentration as CaCO₃ Equivalent

C_{\mathrm{CaCO_3}} = C_{\mathrm{ion}} \times \frac{50.04}{\mathrm{EW}}

Opens with EW = 207.2 g/mol already filled in

Acid Feed to Reduce Alkalinity

\dot m = \frac{\Delta \mathrm{Alk} \, Q \times \frac{\mathrm{EW}}{50.04}}{p/100\%}

Opens with EW = 207.2 g/mol already filled in

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