An atom that undergoes radioactive decay and has a large nucleus most likely has:

a) a neutron number higher than the proton number.
b) a proton number higher than the neutron number.
c) an electron number higher than the proton number.
d) a proton number higher than the electron number.

The atom that undergoes radioactive decay and has a large nucleus most likely has a neutron number higher than the proton number.

Explanation:

Unstable isotopes are defined as the isotopes which have more number of neutrons as compared to the stable form of an atom.

These isotopes attain stability by undergoing a spontaneous nuclear decay. The isotopes which are unstable are also known as radioactive isotopes or radioisotopes.

There are 4 types of radioactive decay by which an unstable nucleus attains stability. They are alpha decay, beta decay, gamma decay and positron decay.

Hence, the atom that undergoes radioactive decay and has a large nucleus most likely has a neutron number higher than the proton number.

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error