---
title: "A student analyzes the set of isoelectronic species shown in the table below.  | Species | Atomic Number (Z) | Number of Electrons | | :— | :—: | :—: | | \\(\\text{O}^{2-}\\) | 8 | 10 | | \\(\\text{F}^-\\)| 9 | 10 | | \\(\\text{Na}^+\\) | 11 | 10 | | \\(\\text{Mg}^{2+}\\) | 12 | 10 |  Which of the following claims correctly identifies the species with the smallest ionic radius and provides the correct justification?"
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url: "https://nerd-notes.com/ubq/119155/"
date_modified: "2026-08-19T12:32:21+00:00"
---

# A student analyzes the set of isoelectronic species shown in the table below.

| Species | Atomic Number (Z) | Number of Electrons |
| :— | :—: | :—: |
| \(\text{O}^{2-}\) | 8 | 10 |
| \(\text{F}^-\)| 9 | 10 |
| \(\text{Na}^+\) | 11 | 10 |
| \(\text{Mg}^{2+}\) | 12 | 10 |

Which of the following claims correctly identifies the species with the smallest ionic radius and provides the correct justification?

A student analyzes the set of isoelectronic species shown in the table below.

| Species | Atomic Number (Z) | Number of Electrons |
| :--- | :---: | :---: |
| \(\text{O}^{2-}\) | 8 | 10 |
| \(\text{F}^-\)| 9 | 10 |
| \(\text{Na}^+\) | 11 | 10 |
| \(\text{Mg}^{2+}\) | 12 | 10 |

Which of the following claims correctly identifies the species with the smallest ionic radius and provides the correct justification?

- **A.** \(\text{O}^{2-}\) has the smallest ionic radius because it has fewer electron shells, resulting in reduced electron-electron repulsion.
- **B.** \(\text{Mg}^{2+}\) has the smallest ionic radius because its electrons occupy fewer energy levels than those of the other species.
- **C.** \(\text{O}^{2-}\) has the smallest ionic radius because its lower nuclear charge exerts a stronger electrostatic attraction per electron.
- **D.** \(\text{Mg}^{2+}\) has the smallest ionic radius because its greater nuclear charge exerts a stronger attractive force on the same number of electrons.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119155/*