Question

Which statement describes the difference between chemical reactions and nuclear decay

Answer 1

Chemical reactions can result in new compounds, while nuclear reactions can result in new elements.

Answer 2

Chemical reactions might be fast -- burning gasoline, or slow -- rusting. Usually the require two or more reactants. Most of these, along with requiring more than 1 substance, also requires something to get it started ... burning needs a spark to start it.
Nuclear decay only requires 1 thing, the radioactive element. Wait and it spontaneously undergoes decay.