In reaction A, each sodium atom gives one electron to a chlorine atom. In reaction B, an isotope of oxygen decays to form an isotope of nitrogen. Which statement best describes the energy that is released per gram by these reactions?

Reaction A is a chemical reaction: sodium transfers an electron to chlorine, changing how the atoms are bonded but not their nuclei. Reaction B changes an oxygen nucleus into a nitrogen nucleus, so it is a nuclear reaction and releases much more energy per gram than a chemical reaction. Therefore, reaction B releases more energy per gram.

AI-written and checked against the verified answer.