Question

1. play with the simulation. which particles affect the mass number of your atom or ion?

Explanation:

The mass number of an atom or ion is the sum of the number of protons and neutrons in its nucleus. Electrons have negligible mass compared to protons and neutrons, so they do not affect the mass number. Protons and neutrons contribute significantly to the mass of the atom/ion, so they are the particles that affect the mass number.

Answer:

Protons and neutrons