95Am

Americium

Actinidesolidblock f

The only synthetic element found in ordinary homes, a fraction of a microgram of americium-241 ionising air inside the smoke detector overhead.

Atomic number	95
Mass number (longest-lived isotope)	243 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] 5f⁷ 7s²

About Americium

An ionisation smoke alarm contains about 0.3 micrograms of americium-241, whose alpha particles keep a small volume of air conducting; smoke particles absorb the alphas, the current drops, and the horn sounds. It is the only place most people will ever be within a metre of a deliberately manufactured element, and roughly a hundred million of them are sold each year. Seaborg's team made americium in late 1944 by successive neutron capture on plutonium, and named it after the Americas by analogy with europium directly above it. Seaborg announced americium and curium not in a journal but on a children's radio quiz show in November 1945, five days before the formal paper, after a young panellist asked whether any new elements had been discovered.

Use 243 g/mol in these solvers

Moles from Mass (n = m/M)

n = \frac{m}{M}

Opens with M = 243 g/mol already filled in

Gas Density from Molar Mass

\rho = \frac{PM}{RT}

Opens with M = 243 g/mol already filled in

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

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

Opens with M = 243 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 = 243 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 = 243 g/mol already filled in

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