explain why isotopes of the same element behave differently in nuclear reactions but not in chemical…

Brief Explanations:

Chemical reactions involve electrons. Isotopes have same electron - configuration, so they have similar chemical behavior. Nuclear reactions involve the nucleus. Isotopes have different numbers of neutrons in the nucleus, which affects nuclear properties and leads to different nuclear behavior.

Answer:

Isotopes of the same element have the same electron - configuration, so they behave the same in chemical reactions which involve electrons. But they have different numbers of neutrons in the nucleus, and since nuclear reactions involve the nucleus, they behave differently in nuclear reactions.