Final Answer:
The described scenario suggests beta decay. In beta decay, a neutron transforms into a proton, releasing a beta particle (electron) and an antineutrino. This results in an increase of one proton in the nucleus.
Step-by-step explanation:
The scenario described suggests that beta decay has occurred. In beta decay, a neutron in the parent nucleus is transformed into a proton, releasing a beta particle (an electron) and an antineutrino. This results in an increase of one proton in the nucleus, changing the element. The daughter atom formed after beta decay has one more proton and one less neutron than the parent.
The mass of the daughter atom being 4 less than the parent aligns with the beta decay process. During beta decay, a neutron is converted into a proton, reducing the mass number by one unit. The emitted beta particle (electron) carries away energy, contributing to the observed decrease in mass. This type of decay is a fundamental process in nuclear physics, and it plays a role in the natural radioactive decay of certain isotopes.