---
title: "The table below provides the atomic numbers and valence electron configurations for four elements in Period 3 of the periodic table.  | Element | Atomic number | Valence electron configuration | | :— | :—: | :— | | \\(\\text{Si}\\) | \\(14\\) | \\(3s^2\\,3p^2\\) | | \\(\\text{P}\\) | \\(15\\) | \\(3s^2\\,3p^3\\) | | \\(\\text{S}\\) | \\(16\\) | \\(3s^2\\,3p^4\\) | | \\(\\text{Cl}\\) | \\(17\\) | \\(3s^2\\,3p^5\\) |  Based on periodic trends and electron configurations, which of the following correctly ranks these elements in order of decreasing first ionization energy?"
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url: "https://nerd-notes.com/ubq/121384/"
date_modified: "2026-08-23T05:02:01+00:00"
---

# The table below provides the atomic numbers and valence electron configurations for four elements in Period 3 of the periodic table.

| Element | Atomic number | Valence electron configuration |
| :— | :—: | :— |
| \(\text{Si}\) | \(14\) | \(3s^2\,3p^2\) |
| \(\text{P}\) | \(15\) | \(3s^2\,3p^3\) |
| \(\text{S}\) | \(16\) | \(3s^2\,3p^4\) |
| \(\text{Cl}\) | \(17\) | \(3s^2\,3p^5\) |

Based on periodic trends and electron configurations, which of the following correctly ranks these elements in order of decreasing first ionization energy?

The table below provides the atomic numbers and valence electron configurations for four elements in Period 3 of the periodic table.

| Element | Atomic number | Valence electron configuration |
| :--- | :---: | :--- |
| \(\text{Si}\) | \(14\) | \(3s^2\,3p^2\) |
| \(\text{P}\) | \(15\) | \(3s^2\,3p^3\) |
| \(\text{S}\) | \(16\) | \(3s^2\,3p^4\) |
| \(\text{Cl}\) | \(17\) | \(3s^2\,3p^5\) |

Based on periodic trends and electron configurations, which of the following correctly ranks these elements in order of decreasing first ionization energy?

- **A.** \(\text{Cl} > \text{S} > \text{P} > \text{Si}\)
- **B.** \(\text{Cl} > \text{P} > \text{Si} > \text{S}\)
- **C.** \(\text{Cl} > \text{P} > \text{S} > \text{Si}\)
- **D.** \(\text{P} > \text{Cl} > \text{S} > \text{Si}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121384/*