---
title: "The photoelectron spectroscopy (PES) data for nitrogen (\\(\\text{N}\\)) and an unknown neutral Period \\(2\\) element, \\(\\text{X}\\), are shown in the table below.  | Peak | Element \\(\\text{N}\\) Binding Energy (\\(\\text{MJ/mol}\\)) | Element \\(\\text{X}\\) Binding Energy (\\(\\text{MJ/mol}\\)) | Relative Peak Area for Element \\(\\text{X}\\) | | :—: | :—: | :—: | :—: | | 1 | \\(39.6\\) | \\(52.6\\) | \\(2\\) | | 2 | \\(2.45\\) | \\(3.04\\) | \\(2\\) | | 3 | \\(1.40\\) | \\(1.31\\) | \\(4\\) |  Based on the data, which of the following identifies element \\(\\text{X}\\) and provides the correct explanation for why the binding energy of Peak 3 is lower for element \\(\\text{X}\\) than for element \\(\\text{N}\\)?"
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url: "https://nerd-notes.com/ubq/119623/"
date_modified: "2026-08-21T08:11:50+00:00"
---

# The photoelectron spectroscopy (PES) data for nitrogen (\(\text{N}\)) and an unknown neutral Period \(2\) element, \(\text{X}\), are shown in the table below.

| Peak | Element \(\text{N}\) Binding Energy (\(\text{MJ/mol}\)) | Element \(\text{X}\) Binding Energy (\(\text{MJ/mol}\)) | Relative Peak Area for Element \(\text{X}\) |
| :—: | :—: | :—: | :—: |
| 1 | \(39.6\) | \(52.6\) | \(2\) |
| 2 | \(2.45\) | \(3.04\) | \(2\) |
| 3 | \(1.40\) | \(1.31\) | \(4\) |

Based on the data, which of the following identifies element \(\text{X}\) and provides the correct explanation for why the binding energy of Peak 3 is lower for element \(\text{X}\) than for element \(\text{N}\)?

The photoelectron spectroscopy (PES) data for nitrogen (\(\text{N}\)) and an unknown neutral Period \(2\) element, \(\text{X}\), are shown in the table below.

| Peak | Element \(\text{N}\) Binding Energy (\(\text{MJ/mol}\)) | Element \(\text{X}\) Binding Energy (\(\text{MJ/mol}\)) | Relative Peak Area for Element \(\text{X}\) |
| :---: | :---: | :---: | :---: |
| 1 | \(39.6\) | \(52.6\) | \(2\) |
| 2 | \(2.45\) | \(3.04\) | \(2\) |
| 3 | \(1.40\) | \(1.31\) | \(4\) |

Based on the data, which of the following identifies element \(\text{X}\) and provides the correct explanation for why the binding energy of Peak 3 is lower for element \(\text{X}\) than for element \(\text{N}\)?

- **A.** Element \(\text{X}\) is \(\text{C}\), because Peak 3 has a lower binding energy as a result of a smaller nuclear charge and weaker Coulombic attraction.
- **B.** Element \(\text{X}\) is \(\text{O}\), because the peak area ratio indicates a \(1s^2 2s^2 2p^4\) configuration, and repulsion between paired electrons in the \(2p\) subshell reduces the energy required to remove an electron.
- **C.** Element \(\text{X}\) is \(\text{O}\), because the peak area ratio indicates a \(1s^2 2s^2 2p^4\) configuration, and increased shielding of the \(2p\) electrons by the core electrons reduces the effective nuclear charge.
- **D.** Element \(\text{X}\) is \(\text{Ne}\), because Peak 3 corresponds to a filled valence shell, and electron shielding between energy levels decreases the binding energy.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119623/*