Which of these characteristics differentiates electrons from protons and neutrons?

a. They do not move.

b. Electrons are larger.

c. Electrons are not in a fixed position.

d. They are located in the nucleus.

C is the correct answer. Electrons are not in a fixed position - they float around the outside of the nucleus in a cloud. In contrast, the protons and neutrons are found inside the nucleus. Electrons are also much smaller than both protons and neutrons.