Which subatomic particle is the smallest in terms of mass?

• A. Electron
• B. Proton
• C. Alpha particle
• D. Neutron

Answer: (A)

Verified step by step guidance

1. Understand the basic properties of subatomic particles: Electrons, protons, neutrons, and alpha particles are all subatomic particles, but they differ in mass and charge.
2. Recall the mass of each particle: Electrons have a mass of approximately \(9.109 \times 10^{-31}\) kg, protons have a mass of approximately \(1.673 \times 10^{-27}\) kg, neutrons have a mass of approximately \(1.675 \times 10^{-27}\) kg, and alpha particles, which consist of 2 protons and 2 neutrons, have a mass of approximately \(6.645 \times 10^{-27}\) kg.
3. Compare the masses: Notice that the electron has a significantly smaller mass compared to protons, neutrons, and alpha particles.
4. Consider the charge: While the charge is not directly related to mass, it is useful to know that electrons have a negative charge, protons have a positive charge, neutrons are neutral, and alpha particles have a positive charge due to their protons.
5. Conclude based on mass comparison: Since the electron has the smallest mass among the listed subatomic particles, it is the correct answer to the question.