Answer the following question given this paragraph: 

Rutherford’s atomic model became known as the nuclear model . In the nuclear atom, the protons and neutrons, which comprise nearly all of the mass of the atom, are located in the nucleus at the center of the atom. The electrons are distributed around the nucleus and occupy most of the volume of the atom. It is worth emphasizing just how small the nucleus is compared to the rest of the atom. If we could blow up an atom to be the size of a large professional football stadium, the nucleus would be about the size of a marble.


Q: In an atom, what two major types of particles are located in the nucleus?

 Choices:

- electrons and neutrons

- molecules and neutrons

- ions and electrons

- protons and neutrons

A:
protons and neutrons
