97Bk

Berkelium

Actinidesolidblock f

A synthetic actinide produced only in milligrams, and the target material bombarded with calcium to create element 117, tennessine.

Atomic number	97
Mass number (longest-lived isotope)	247 g/mol
This element has no stable isotope, so it has no standard atomic weight. The figure above is the mass number of its longest-lived isotope — a convention, not a measurement of a natural mixture.
Group · period	f-block series · 7
Electron configuration	[Rn] 5f⁹ 7s²

About Berkelium

Berkelium is named for the city of Berkeley, in conscious parallel with terbium's Ytterby, and its symbol Bk was chosen over the more obvious Be because beryllium already had it. It exists in quantities measured in tens of milligrams: the Oak Ridge High Flux Isotope Reactor produces berkelium-249 by long irradiation of curium, and a full campaign yields perhaps 50 mg after two years. That scarcity is the whole story of element 117. Making tennessine required 22 mg of berkelium-249 flown from Tennessee to Dubna and used within months, because its 330-day half-life means the target is decaying into californium the whole time the experiment is running.

Use 247 g/mol in these solvers

Moles from Mass (n = m/M)

n = \frac{m}{M}

Opens with M = 247 g/mol already filled in

Gas Density from Molar Mass

\rho = \frac{PM}{RT}

Opens with M = 247 g/mol already filled in

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

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

Opens with M = 247 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 = 247 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 = 247 g/mol already filled in

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