102No

Nobelium

Actinidesolidblock f

An actinide whose discovery claim was so contested that the name given in Stockholm survived even after the claim behind it had collapsed.

Atomic number	102
Mass number (longest-lived isotope)	259 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] 5f¹⁴ 7s²

About Nobelium

The Nobel Institute in Stockholm announced element 102 in 1957 and proposed the name nobelium; neither Berkeley nor Dubna could reproduce the result, and the Swedish claim was withdrawn, but by then the name was in the textbooks and it stuck. IUPAC eventually credited the discovery to Dubna in 1966 while leaving the Swedish name in place — an outcome nobody designed and everybody accepted. Chemically nobelium is the standout of the late actinides: the filled 5f¹⁴ shell makes the 2+ state more stable than the 3+ state, so in solution it behaves more like an alkaline earth than like the actinides around it, which is exactly the kind of relativistic deviation that makes heavy-element chemistry worth doing.

Use 259 g/mol in these solvers

Moles from Mass (n = m/M)

n = \frac{m}{M}

Opens with M = 259 g/mol already filled in

Gas Density from Molar Mass

\rho = \frac{PM}{RT}

Opens with M = 259 g/mol already filled in

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

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

Opens with M = 259 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 = 259 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 = 259 g/mol already filled in

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