Which of the following best explains why both nuclear and chemical changes can occur in matter?

• A. Because both involve changes in the energy and structure of atoms, but at different levels.
• B. Because both are reversible processes under all conditions.
• C. Because both only involve the rearrangement of electrons in atoms.
• D. Because both always result in the formation of new elements.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the difference between nuclear and chemical changes. Chemical changes involve the rearrangement of electrons in atoms, affecting how atoms bond together, but the nuclei of the atoms remain unchanged.
2. Step 2: Recognize that nuclear changes involve changes in the nucleus of the atom, such as the number of protons or neutrons, which can result in the formation of new elements or isotopes.
3. Step 3: Note that both nuclear and chemical changes involve changes in energy and structure, but at different scales: chemical changes affect electron arrangements and energy levels, while nuclear changes affect the nucleus and nuclear energy.
4. Step 4: Evaluate the answer choices by comparing them to these concepts: chemical changes do not change the nucleus, nuclear changes can form new elements, and not all changes are reversible.
5. Step 5: Conclude that the best explanation is that both nuclear and chemical changes involve changes in the energy and structure of atoms, but at different levels (electrons vs. nucleus).