---
title: "The potential energy curves for the formation of homonuclear diatomic molecules of two halogens, \\(\\text{Cl}_2\\text{(g)}\\) and \\(\\text{Br}_2\\text{(g)}\\), from their isolated ground-state atoms are shown in the graph. Based on the principles of atomic structure and chemical bonding, which curve corresponds to \\(\\text{Cl}_2\\text{(g)}\\), and what is the correct justification?"
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url: "https://nerd-notes.com/ubq/119589/"
date_modified: "2026-08-21T06:54:05+00:00"
---

# The potential energy curves for the formation of homonuclear diatomic molecules of two halogens, \(\text{Cl}_2\text{(g)}\) and \(\text{Br}_2\text{(g)}\), from their isolated ground-state atoms are shown in the graph. Based on the principles of atomic structure and chemical bonding, which curve corresponds to \(\text{Cl}_2\text{(g)}\), and what is the correct justification?

The potential energy curves for the formation of homonuclear diatomic molecules of two halogens, \(\text{Cl}_2\text{(g)}\) and \(\text{Br}_2\text{(g)}\), from their isolated ground-state atoms are shown in the graph. Based on the principles of atomic structure and chemical bonding, which curve corresponds to \(\text{Cl}_2\text{(g)}\), and what is the correct justification?

![A graph of potential energy versus internuclear distance with bare perpendicular axes. The horizontal axis is labeled Internuclear Distance (\(\text{pm}\)), starting at 0. The vertical axis is labeled Potential Energy (\(\text{kJ/mol}\)), with a horizontal dashed reference line at 0. Two curves are drawn below zero. Curve 1 is a solid line that drops steeply from positive energy to a deep minimum at a smaller internuclear distance, then curves upward to approach zero from below. Curve 2 is a dashed line that drops from positive energy to a shallower minimum located further to the right at a larger internuclear distance and higher potential energy than Curve 1, then curves upward to approach zero from below. Curve 1 and Curve 2 are explicitly labeled with text and leader lines pointing to their respective curves. No other particles, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787295244-pIgUP9.jpg)

- **A.** Curve 1, because \(\text{Cl}\) has a smaller atomic radius than \(\text{Br}\), allowing a shorter equilibrium bond length and a stronger bond with a deeper potential energy minimum.
- **B.** Curve 1, because \(\text{Cl}\) has a higher electronegativity than \(\text{Br}\), causing increased nuclear repulsion that shifts the potential energy minimum to a higher energy.
- **C.** Curve 2, because \(\text{Cl}\) atoms have fewer occupied electron shells than \(\text{Br}\), resulting in less electron shielding and a longer equilibrium bond length.
- **D.** Curve 2, because the smaller atomic size of \(\text{Cl}\) reduces orbital overlap, resulting in a weaker bond with a shallower potential energy minimum.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119589/*