What describes a decay chain?

• A. A single decay that directly yields a stable atom.
• B. A chemical transformation with no change in nucleus.
• C. A series of radioactive decays that eventually yields a stable atom.
• D. A process that increases radioactivity.

Answer: (C)

A decay chain is a series of radioactive decays where an unstable nucleus changes step by step, eventually becoming a stable nucleus. With each decay, the nucleus transforms into a new nuclide, which may itself be unstable and continue the sequence, releasing radiation along the way. This process involves changes in the nucleus (protons and neutrons), not just electrons, which is why it’s nuclear in nature rather than a chemical transformation. It differs from a single decay that would directly yield a stable atom; instead, the chain shows multiple events occurring one after another until stability is reached, as seen in examples like uranium-238 decaying through several intermediates to lead-206.