The modern IUPAC atomic mass scale relies exclusively on the Carbon-12 () isotope as the universal reference standard, superseding the older scale based on naturally occurring Oxygen (). What are the

Question

The modern IUPAC atomic mass scale relies exclusively on the Carbon-12 ($^{12}C$) isotope as the universal reference standard, superseding the older scale based on naturally occurring Oxygen ($^{16}O$). What are the primary scientific advantages of utilizing $^{12}C$ as the standard?

Prashant Kotian · Accepted Answer

Correct answer: A,C. The transition to the standard was motivated by minimizing the discrepancy between the physicists' scale (which used pure ) and the chemists' scale (which used the natural isotopic mixture of oxygen, causing continuous fluctuations as isotopic abundances varied slightly by source). Using resolved this, keeping the relative masses of most elements nearly identical to the older chemical scale and very close to whole numbers. Option B is factually incorrect (Oxygen is far more abundant in the crust). Option D is scientifically irrelevant to mass spectrometry scaling.

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