The first model represents the proton and neutron distribution in the nucleus of four helium isotopes. The second image shows the entry for helium in the periodic table. Based on the information in the periodic table, which is the most common isotope of helium?

Helium exist as an isotope, its most common isotope is the one that is placed on the periodic table. The helium atom on the periodic table has two electrons, two protons and two neutrons. The proton and the neutron are located inside the nucleus, this means that two protons and two neutrons can be found inside the helium nucleus. Thus, in the pictures given above, the correct picture is the one that contain four particles.

Explanation: