The atomic number and mass number play important roles in how stable an element is. Here’s a simple breakdown:

1. Atomic Number:

   • This number tells us how many protons are in the nucleus of an atom.
   • It also tells us what the element is.
   • For an element to be stable, it needs to have a good balance between protons and neutrons.
   • If there are too many or too few neutrons, the element can become radioactive.

2. Mass Number:

   • The mass number is the total number of protons and neutrons in an atom.
   • Elements with a higher mass number may have unstable versions called isotopes.
   • These unstable isotopes can break down over time in a process called decay.

In the end, looking at these numbers helps us figure out why some elements are stable and others are not!