Why do all isotopes of an element have the same chemical properties?

• A. Because they have the same number of neutrons in the nucleus.
• B. Because they have the same atomic mass.
• C. Because they have the same number of electrons and the same electron configuration.
• D. Because they have different numbers of protons.

Answer: (C)

Verified step by step guidance

1. Recall that chemical properties of an element are primarily determined by the arrangement and behavior of its electrons, especially the valence electrons.
2. Understand that isotopes of an element have the same number of protons (which defines the element) but differ in the number of neutrons in the nucleus.
3. Since isotopes have the same number of protons, they also have the same number of electrons when neutral, leading to identical electron configurations.
4. Recognize that because chemical reactions involve interactions between electrons, isotopes exhibit the same chemical properties despite differences in nuclear composition.
5. Conclude that differences in neutron number affect nuclear properties (like stability and mass) but do not influence the chemical behavior governed by electron configuration.