Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

Why do isotopes of the same element behave identically in chemical reactions?

1. They have different numbers of neutrons

2. They have different atomic masses

3. They have the same number of protons

4. They have different chemical properties

The correct answer is: They have the same number of protons

Isotopes of the same element behave identically in chemical reactions primarily because they have the same number of protons. The number of protons in an atom determines its chemical identity and properties. Since isotopes are variations of the same element, they share the same number of protons, which means they occupy the same position in the periodic table and have similar behavior in chemical reactions. Chemical reactions involve the interactions of electrons, particularly those in the outermost shell, rather than the nucleus. Since isotopes have the same electron configuration due to their identical number of protons, their chemical properties remain consistent across the different isotopes of an element. Other factors, such as having different numbers of neutrons and different atomic masses, do not influence the chemical behavior of the element because the neutron count affects only the mass and stability of the nucleus, not the interactions that take place during chemical reactions.