-A helium atom is an atom of the chemical element helium.
-Helium is composed of two electrons bound by the electromagnetic force to a nucleus containing two protons along with either one or two neutrons, depending on the isotope, held together by the strong force.
With the information given in the question, we can only observe that they are quite SIMILAR in at least one respect ... both the real ones and those in 'this model' are quite invisible and intangible, and we must take your word for it that they exist at all.
Like so many others in math and science, this question raises another question: "Which model are you talking about ?"
Although the semi truck certainly has a larger mass, it is not in motion and therefore does not have any momentum. The bicycle however has both mass and velocity and therefore has the larger momentum of the pair.
