Paper 3 · Nuclear Physics and Radioactivity
In terms of nuclear constituents, what is meant by isotopes?
Model answer
same protons, different neutrons
Also accepted: same proton no, diff mass no
Explanation: Isotopes are atoms of the same element (same proton/atomic number) but with different numbers of neutrons, so different mass numbers.
Derived from ZIMSEC Physics Paper 3, November 2002, Q6