Question

As the number of protons and neutrons in the nucleus increases, elements are much less likely to form stable, non-radioactive isotopes. of elements that form non-radioactive isotopes, which has the highest atomic number?

Answer 1

Bismuth

Step-by-step explanation:

The highest atomic numbered element for which nonradioactive isotopes exist is bismuth (Bi). All known nuclides of every element with an atomic number greater than 83 are unstable (radioactive). Thus, the number of nucleons that can be packed into a stable nucleus appears to be limited. This limit is 209, which is reached with bismuth-209, the largest known stable nucleus.

Answer 2

The answer is iron. Iron has an atomic number of 26. This means than iron has 26 protons in it's nucleus. However, not all iron atoms have the same number of neutrons. Most commonly iron has 30 neutrons, but it also has 3 other stable isotopes. The word stable is important here because unstable elements are radioactive.