Ineed . i’m stuck on this question. asap! the number of protons in the nucleus of an atom of an element is the of that element i don’t know what it is

The number of protons in the nucleus of an atom of an element is the atomic number of that element.

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.