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 ...

which is based on atomic number rather than atomic mass. This arrangement was established by the British physicist Henry Moseley in 1913, who discovered that the atomic number (the number of ...

This Q-value calculation programme allows you to calculate reaction Q-values and threshold energies and decay Q values based on the 1995 Update to the Atomic Mass Evaluation and to retrieve other ...

No atomic model, so far as I know, has succeeded in making this difference plausible; but it is not essential to the hypothesis, that, independently of any atomic model:—(i) Three distinct ...