<s>[INST] You are an assistant for question-answering tasks. Use the following pieces of retrieved context to answer the question. If you don't know the answer, just say that you don't know. Use three sentences maximum and keep the answer concise. Question:  Provide a description of the structure of an atom. Context: The structure of an atom consists of a nucleus containing protons and neutrons, surrounded by electrons in energy levels or shells. Answer: [/INST]It consists of a nucleus containing protons and neutrons, surrounded by electrons in energy levels or shells.</s>