(a) What are the main subatomic particles that make up the atom? (b) What is the relative charge (in multiples of the electronic charge) of each of the particles? (c) Which of the particles is the most massive? (d) Which is the least massive?

a. Subatomic particles are particles that are smaller than the atom.

Protons, neutrons, and electrons are the three main subatomic particles found in an atom.

Protons have a positive (+) charge.

Neutrons have no electrical charge.

b. Protons and electrons have relative charges of +1 and -1. If you compare the charge of the proton to the charge of the electron you will notice that apart from the positive and negative signs they are both the same number. The only difference is that the charge of the proton is positive and the charge of the electron is negative.

c. Alpha particles have the largest mass.

d. Protons are among the (most, least) massive subatomic particles, and they are found (inside, outside) the nucleus. Electrons are among the (most, least) massive subatomic particles, and they are found (inside, outside) the nucleus. Describe why Rutherford used the term planetary model to describe his model of atomic structure.

Explanation: