How is the mass number of an isotope expressed in the name of an atom?
The mass number, the number of nuclear particles, is usually expressed as a superscript to the right of the elemental symbol.
If we take the hydrogen atom as an exemplar, most hydrogen atoms contain the one proton in their nuclei, i.e. the
A few hydrogen atoms contain the 1 proton and a neutron in their nuclei: this is the
As I have written before,