An atom of an element that has the same number of protons but different numbers of neutrons is called a(n) *

It's called an isotope.

For example, in the element hydrogen, it has 3 stable Isotopes. These include the hydrogen atom with no neutrons, 1 neutron, and 2 neutrons. They're still an hydrogen atom, as they still have 1 proton, but they're Isotopes of hydrogen.

Each element has a different number of stable Isotopes, some may get only one, but some may get a lot.

Note that Isotopes is only the different numbers in neutrons, but not proton or electrons.

It was necessary to redeem the world and he knew that his son was the only way