Which of the following statements about nuclear reaction is correct? The reaction

Analyze the question: We are asked which statement correctly describes a nuclear reaction.

Concept: A nuclear reaction is a change that happens in the nucleus of an atom. Examples are radioactive decay, nuclear fission and nuclear fusion. The nucleus changes, so a new element is often formed. It is very different from a chemical reaction, which involves only the outer (valence) electrons.

Evaluate each option:

• A. Involves neutrons only: Wrong. Nuclear reactions involve both protons and neutrons (nucleons). Alpha decay, for example, emits 2 protons and 2 neutrons.
• B. Takes place inside the nucleus: Correct. The changes happen in the nucleus, such as the emission of alpha or beta particles, or the splitting or joining of nuclei.
• C. Is governed by temperature and pressure: Wrong. Nuclear reactions, such as radioactive decay, are largely unaffected by temperature, pressure or chemical state. Chemical reactions are the ones that depend on these conditions.
• D. Involves protons and electrons only: Wrong. Neutrons are also involved, and nuclear reactions are not limited to protons and electrons.

Answer: B. A nuclear reaction takes place inside the nucleus.

Exam tip: Remember "Nuclear = Nucleus, Chemical = Electrons." If an option says a reaction depends on temperature or pressure, it is describing a chemical reaction, not a nuclear one.