Which of the following ions has the smallest radius? — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

I need to see the answer choices to explain why C is correct. Could you please provide the options (A, B, C, D)? However, here's the **general principle** for comparing ionic radii: **Factors determining ionic radius (in order of importance):** 1. **Nuclear charge (atomic number)** — More protons → smaller radius 2. **Number of electron shells** — More shells → larger radius 3. **Charge of ion** — Higher positive charge → smaller radius; higher negative charge → larger radius **Step-by-step approach:** - Compare ions in the **same period** (same number of shells): The one with **highest positive charge** is smallest - Compare ions with **same charge**: The one with **fewest shells** is smallest - For **isoelectronic ions** (same electron configuration): The one with **highest nuclear charge** is smallest **Example:** If options were $Na^+$, $Mg^{2+}$, $Al^{3+}$, $Cl^-$: - All in period 3 except $Cl^-$ - $Al^{3+}$ has the most protons and fewest electrons among cations - **$Al^{3+}$ would be smallest** Please share the specific ions in options A, B, C, D so I can provide the complete solution!