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But that average is not the same every place on Earth, ... So, now instead of carbon listed as being 12.0107 atomic mass units with a measurement uncertainty of about 0.0008, ...

Atomic structure - AQA Calculating relative atomic mass. ... It is the number of times heavier an atom is than one-twelfth of a carbon-12 atom. of an element is the average mass of its atoms, ...

For example, a helium atom has an atomic mass of 4, but an atomic number (or positive charge) of 2. Since electrons have almost no mass, it seemed that something besides the protons in the nucleus ...

The quest for the value of the electron’s atomic mass has been the subject of continuing efforts over the past few decades 1,2,3,4.Among the seemingly fundamental constants that parameterize the ...