Why is the Bohr atom described as a planetary model?

• A. Because the atom emits light only when electrons collide with the nucleus.
• B. Because the nucleus contains protons and neutrons arranged in concentric circles.
• C. Because electrons orbit the nucleus in fixed paths similar to planets orbiting the sun.
• D. Because electrons are randomly distributed around the nucleus like asteroids in space.

Answer: (C)

Verified step by step guidance

1. Understand the Bohr model of the atom: It proposes that electrons move around the nucleus in specific, fixed circular orbits or energy levels.
2. Recognize the analogy to the solar system: Just as planets orbit the sun in defined paths, electrons orbit the nucleus in these fixed paths without radiating energy.
3. Note that this model contrasts with earlier models where electrons were thought to be randomly distributed or continuously losing energy.
4. The term 'planetary model' comes from this similarity between electron orbits and planetary orbits, emphasizing the structured, quantized nature of electron movement.
5. Therefore, the Bohr atom is described as a planetary model because it depicts electrons orbiting the nucleus in fixed paths, analogous to planets orbiting the sun.