Question

the charged particles in the beams that thomson studied came from atoms. as these particles moved away from their original atoms, they formed a visible beam. the current model of the atom includes protons, neutrons, and electrons.
what is the best use of an atomic model to explain the charge of the particles in thomsons beams?
○ an atom’s negative particles are surrounded by positive matter, so the positive particles are easier to remove.
○ an atom’s positive particles are surrounded by negative matter, so the negative particles are easier to remove.
○ an atom’s smaller negative particles are at a distance from the central positive particles, so the negative particles are easier to remove.
○ an atom’s larger positive particles are at a distance from the central negative particles, so the positive particles are easier to remove.

Explanation:

1. Recall Thomson's work and atomic structure: Thomson discovered electrons (negative particles). The current atomic model has a nucleus with positive protons (and neutrons) and electrons (negative, smaller) in electron cloud around the nucleus.
2. Analyze each option:

• Option 1: Says positive particles are easier to remove, but Thomson's beams had negative particles (electrons), so incorrect.
• Option 2: Old "plum - pudding" model (positive matter with negative particles), but current model is different. Also, the reasoning about removal is off.
• Option 3: Matches current model: electrons (smaller, negative) are at a distance from central positive protons/neutrons (nucleus). Since they are at a distance, they are easier to remove (like in cathode ray experiment, electrons were removed).
• Option 4: Positive particles are not larger or at a distance from central negative (nucleus is positive, electrons are negative and around), so incorrect.

Answer:

C. An atom’s smaller negative particles are at a distance from the central positive particles, so the negative particles are easier to remove.