Which type of ion generally has a larger ionic radius, and what is the main reason for this difference?

• A. Negative ions (anions) are smaller because they have more electrons, which are pulled closer to the nucleus.
• B. Negative ions (anions) are larger because they gain electrons, increasing electron-electron repulsion and expanding the electron cloud.
• C. Positive ions (cations) are smaller because they gain electrons, increasing electron-electron repulsion.
• D. Positive ions (cations) are larger because they lose electrons, reducing nuclear attraction and allowing the ion to expand.

Answer: (B)

Verified step by step guidance

1. Understand that ionic radius refers to the size of an ion, which depends on the balance between the nuclear charge (number of protons) and the number of electrons.
2. Recognize that negative ions (anions) form when an atom gains electrons, increasing electron-electron repulsion in the electron cloud.
3. Know that this increased repulsion causes the electron cloud to expand, making anions larger than their neutral atoms.
4. Conversely, positive ions (cations) form when an atom loses electrons, reducing electron-electron repulsion and allowing the remaining electrons to be pulled closer to the nucleus.
5. Therefore, anions generally have larger ionic radii than cations mainly because gaining electrons increases repulsion and expands the electron cloud.