---
title: "A neutral chromium atom has \\(24\\) electrons. Spectroscopic measurements show that its ground-state electron configuration deviates from the standard Aufbau filling sequence. Which of the following identifies the correct ground-state electron configuration of a neutral \\(\\text{Cr}\\) atom and provides the best justification for this configuration?"
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url: "https://nerd-notes.com/ubq/119972/"
date_modified: "2026-08-21T08:31:20+00:00"
---

# A neutral chromium atom has \(24\) electrons. Spectroscopic measurements show that its ground-state electron configuration deviates from the standard Aufbau filling sequence. Which of the following identifies the correct ground-state electron configuration of a neutral \(\text{Cr}\) atom and provides the best justification for this configuration?

A neutral chromium atom has \(24\) electrons. Spectroscopic measurements show that its ground-state electron configuration deviates from the standard Aufbau filling sequence. Which of the following identifies the correct ground-state electron configuration of a neutral \(\text{Cr}\) atom and provides the best justification for this configuration?

- **A.** \([\text{Ar}]\, 4s^2 3d^4\), because the \(4s\) subshell is lower in energy than the \(3d\) subshell, requiring the \(4s\) orbital to be completely filled before the \(3d\) orbitals are occupied.
- **B.** \([\text{Ar}]\, 4s^2 3d^4\), because pairing two electrons in the \(4s\) orbital increases the effective nuclear charge experienced by the \(3d\) electrons.
- **C.** \([\text{Ar}]\, 4s^1 3d^5\), because distributing the six valence electrons across six separate orbitals minimizes electron-electron repulsions, resulting in a lower overall energy state.
- **D.** \([\text{Ar}]\, 4s^1 3d^5\), because achieving a half-filled \(3d\) subshell increases the effective nuclear charge of the chromium nucleus.

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