---
title: "A student compares experimental data for fluorine and chlorine, as shown in the table below.  | Element | Electronegativity (Pauling scale) | First electron affinity (kJ/mol) | | :— | :— | :— | | \\(\\text{F}\\) | \\(4.0\\) | \\(-328\\) | | \\(\\text{Cl}\\) | \\(3.0\\) | \\(-349\\) |  Which of the following statements best accounts for why the first electron affinity of \\(\\text{Cl}\\) is more exothermic than that of \\(\\text{F}\\), even though \\(\\text{F}\\) has a higher electronegativity?"
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url: "https://nerd-notes.com/ubq/120178/"
date_modified: "2026-08-21T16:02:50+00:00"
---

# A student compares experimental data for fluorine and chlorine, as shown in the table below.

| Element | Electronegativity (Pauling scale) | First electron affinity (kJ/mol) |
| :— | :— | :— |
| \(\text{F}\) | \(4.0\) | \(-328\) |
| \(\text{Cl}\) | \(3.0\) | \(-349\) |

Which of the following statements best accounts for why the first electron affinity of \(\text{Cl}\) is more exothermic than that of \(\text{F}\), even though \(\text{F}\) has a higher electronegativity?

A student compares experimental data for fluorine and chlorine, as shown in the table below.

| Element | Electronegativity (Pauling scale) | First electron affinity (kJ/mol) |
| :--- | :--- | :--- |
| \(\text{F}\) | \(4.0\) | \(-328\) |
| \(\text{Cl}\) | \(3.0\) | \(-349\) |

Which of the following statements best accounts for why the first electron affinity of \(\text{Cl}\) is more exothermic than that of \(\text{F}\), even though \(\text{F}\) has a higher electronegativity?

- **A.** Chlorine releases more energy because the valence shell of \(\text{Cl}\) experiences a significantly greater effective nuclear charge than that of \(\text{F}\), producing a stronger attraction for the incoming electron.
- **B.** Chlorine releases more energy because an electron added to \(\text{F}\) experiences substantial electron-electron repulsions within the compact \(2p\) subshell, whereas the larger, more diffuse \(3p\) subshell of \(\text{Cl}\) accommodates the extra electron with less repulsion.
- **C.** Chlorine releases more energy because the incoming electron in \(\text{Cl}\) enters an unoccupied \(3d\) orbital that provides additional energetic stabilization not accessible in the \(n = 2\) shell of \(\text{F}\).
- **D.** Chlorine releases more energy because \(\text{Cl}\) has a larger atomic radius than \(\text{F}\), which allows the incoming electron to get closer to the positively charged nucleus without encountering core shielding.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/120178/*