---
title: "The alkali metals in Group 1 of the periodic table display regular periodic trends in their physical and chemical properties. Which of the following lists correctly ranks the elements \\(\\text{Li}\\), \\(\\text{Na}\\), \\(\\text{K}\\), and \\(\\text{Rb}\\) in order of decreasing first ionization energy, and provides the correct justification?"
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url: "https://nerd-notes.com/ubq/119997/"
date_modified: "2026-08-21T08:31:42+00:00"
---

# The alkali metals in Group 1 of the periodic table display regular periodic trends in their physical and chemical properties. Which of the following lists correctly ranks the elements \(\text{Li}\), \(\text{Na}\), \(\text{K}\), and \(\text{Rb}\) in order of decreasing first ionization energy, and provides the correct justification?

The alkali metals in Group 1 of the periodic table display regular periodic trends in their physical and chemical properties. Which of the following lists correctly ranks the elements \(\text{Li}\), \(\text{Na}\), \(\text{K}\), and \(\text{Rb}\) in order of decreasing first ionization energy, and provides the correct justification?

- **A.** \(\text{Li} > 	ext{Na} > 	ext{K} > 	ext{Rb}\), because valence electrons occupy shells at greater average distances from the nucleus down the group, resulting in weaker Coulombic attraction to the nucleus.
- **B.** \(\text{Li} > 	ext{Na} > 	ext{K} > 	ext{Rb}\), because the effective nuclear charge decreases significantly down the group due to increased shielding from core electrons.
- **C.** \(\text{Rb} > 	ext{K} > 	ext{Na} > 	ext{Li}\), because the increasing number of protons in the nucleus down the group exerts a stronger nuclear attraction that holds the valence electron more tightly.
- **D.** \(\text{Rb} > 	ext{K} > 	ext{Na} > 	ext{Li}\), because heavier atoms have more total electrons, requiring greater overall energy to remove an electron.

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