Question

During radioactive decay, the __________ isotope decays into a ____________ isotope that has a different ___________________ number.

Answer 1

Answer: Please find answer in explanation column

Explanation:

During radioactive decay, the __unstable ________ isotope decays into a _stable ___________ isotope that has a different ____proton _______________ number

Or

During radioactive decay, the _ unstable parent nuclide ________ isotope decays into a _stable daughter nuclide ___________ isotope that has a different ____proton _______________ number.

There are 3 types of radioactive decay;alpha, beta and gamma, Of which the above clearly explains the beta decay. In beta decay, the unstable isotope having excess neutrons  will undergo a beta decay emitting a beta particle.( ⁰₋₁e) causing the nucleus to loose a neutron but gain a proton.

Some heavy unstable isotopes which undergo radioactive (beta decay ) to become stable isotopes  are phosphorus-32, strontium-90, iodine-131

Using Strontium 90 as an example , we have

⁹⁰₃₈St ----->⁹⁰₃₉Y + ⁰₋₁e

Strontium an unstable isotope undergoes a beta radioactive decay to form Yttrium.