Question

Standard scale to measure the mass of an atom

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Answer 1

The mass of C-12 isotope was taken as 12 atomic mass units. The scale in which the relative atomic masses of different atoms are expressed is called atomic mass unit scale or amu scale. (In the recent years, the new symbol 'u' (which means unified mass) is recommended to be used in place of amu.

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Answer 2

Answer:

Since 1961 the standard unit of atomic mass has been one-twelth the mass of an atom of the

isotope carbon-12. An isotope is one of two or more species of atoms of the same chemical element that have different atomic mass numbers (protons + neutrons).