Question

An atom that undergoes radioactive decay and has a large nucleus most likely contains a high neutron-proton ratio. a low neutron-proton ratio. more protons than electrons. more electrons than protons.

Answer 1

The answer is; a high neutron-proton ratio

Isotopes have the same number of protons  (atomic number) but differ in the number of neutrons (hence also in their mass numbers). Isotopes are named according to their mass numbers; example carbon-12, and carbon-14. Their atomic numbers remain as 6 but neutron numbers differ (6 and 8).