Z (the atomic number) is the number of protons in an atom's nucleus while A (the mass number) is the number of protons and neutrons in an atom.
Work Step by Step
Z defines the element, A indicates its mass.
You can help us out by revising, improving and updating this answer.Update this answer
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.