In a typical diagram of an atom, label A points to the dense central region, and label B points to the surrounding cloud. What do labels A and B most likely represent?

• A. A: neutron; B: electron
• B. A: electron cloud; B: nucleus
• C. A: proton; B: neutron
• D. A: nucleus; B: electron cloud

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the structure of an atom. An atom consists of a dense central region called the nucleus, which contains protons and neutrons, and a surrounding area called the electron cloud, where electrons are found.
2. Step 2: Identify what label A points to. Since label A points to the dense central region, it most likely represents the nucleus, which is the compact core of the atom containing protons and neutrons.
3. Step 3: Identify what label B points to. Label B points to the surrounding cloud, which corresponds to the electron cloud, the region where electrons move around the nucleus.
4. Step 4: Eliminate incorrect options by matching the labels to their correct atomic components. For example, 'neutron' and 'electron' are particles, not regions; 'electron cloud' and 'nucleus' are regions; 'proton' and 'neutron' are both inside the nucleus, so they cannot represent the central region and the surrounding cloud respectively.
5. Step 5: Conclude that the correct identification is label A as the nucleus and label B as the electron cloud, matching the typical atomic diagram.