Simple Atomic Model

Steps:

• Identify the simple model as the planetary or Bohr model of the atom.
• Recognize the central component as the nucleus, containing protons and neutrons.
• Note that electrons are negatively charged particles orbiting the nucleus.
• Match X to the orbiting particle (electron) and Y to the center (nucleus).

Why A is correct:

• In the basic atomic model, electrons orbit the nucleus, as defined by Rutherford's nuclear model and Bohr's quantization.

Why the others are wrong:

• B: Neutrons reside in the nucleus, not orbiting electrons.
• C: Protons are in the nucleus, not orbiting neutrons.
• D: Protons do not orbit neutrons; both are nuclear components.

Final answer: A