Question

which statement describes what happens to elements during radioactive decay?
○ they release energy.
○ they gain new particles.
○ they lose energy at a varying rate.
○ they have a consistent number of particles.

Explanation:

In nuclear decay (radioactive decay), the number of particles (protons, neutrons) in the nucleus of an atom changes as the atom transforms into another element or isotope. However, the key here is understanding the conservation or change: during nuclear decay, elements (specifically their atomic nuclei) undergo changes where they release energy (in the form of radiation like alpha, beta, gamma). Let's analyze each option:

• "They release energy": Nuclear decay processes (like alpha, beta, gamma decay) involve the nucleus releasing energy (e.g., gamma rays are high - energy photons, and the decay process itself releases energy as the nucleus transitions to a more stable state).
• "They gain new particles": In nuclear decay, the nucleus typically loses particles (alpha decay loses 2 protons and 2 neutrons; beta decay involves a neutron turning into a proton and emitting an electron/positron, so it's a transformation of particles, not gaining new ones from outside).
• "They lose energy at a varying rate": The rate of energy loss (decay rate) for a radioactive substance is characterized by a half - life, which is constant for a given isotope (exponential decay), so the rate is consistent (not varying) for a particular isotope.
• "They have a consistent number of particles": Nuclear decay changes the number of protons/neutrons (e.g., alpha decay reduces the mass number by 4 and atomic number by 2), so the number of particles changes.

So the correct statement is that they release energy.

Answer:

The correct option is: They release energy.