What is the effective nuclear charge (Zeff) of Li?

Question

BlackTom AI · Accepted Answer

First, recall the concept: effective nuclear charge Zeff is the net positive charge experienced by the valence electron after screening by inner electrons. For lithium (Li), the atomic number Z is 3, and the electron configuration is 1s2 2s1. The two electrons in the 1s shell shield the outer 2s electron from the full pull of the nucleus.

Option a: +3. This would imply no shielding at all, i.e., the valence electron feels the full nuclear charge. In Li, there are inner electrons that screen, so +3 is too high.

Option b: +5. This is greater than the actual nuclear charge Z=3, which is impossible for Zeff. It disregards shielding entirely and exceeds the atom’s positive charge.

Option c: +2. If the two 1s electrons provided some shielding, Zeff could be reduced to +2, but in Li specifically the shielding of the single valence electron by the two 1s electrons typically results in a Zeff closer to +1 rather than +2.

Option d: +4. This is also greater than Z and ignores shielding, making it physically implausible for Li’s single valence electron to experience such a strong net charge.

Option e: +1. This aligns with the standard calculation: Zeff ≈ Z − S, with Z = 3 and S ≈ 2 from the 1s electrons, giving Zeff ≈ 1. The outer electron in Li experiences only a modest net attraction due to partial shielding by the inner shell.

In summary, considering the electron configuration and the shielding effect of the inner electrons, the most accurate Zeff value for Li’s valence electron is +1. The other options either neglect shielding entirely, overshoot the nuclear charge, or assume unrealistic levels of shielding for this simple atom.

What is the effective nuclear charge (Zeff) of Li?Single choice

Similar Questions

In a poly-electronic atom, the effective nuclear charge (Zeff) felt by the outermost electron must be larger than the nuclear charge (Z).

What is the effective nuclear charge (Zeff) for a valence electron in an aluminum (Al) atom? (core electrons contribute 0.85 and valence electrons contribute 0.35 to the shielding value, S)

Which of the following feels the strongest effective nuclear charge? (for its valence electrons)

_________ is the reason behind most of your other horizontal trends.

Question 30 Choose a, b, c or d as the best answer. The author’s main argument is that the 100:80:100 model __________.

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler