Intermediate Topic 91 of 1102 Atomic Structure & Periodicity
Pauling Scale
A relative electronegativity scale based on bond energies, with fluorine at 3.98.
Practise Atomic Structure & Periodicity All Atomic Structure & Periodicity topics
In-depth explanation of Pauling Scale
The Pauling scale is the most widely used electronegativity scale, and it is derived from bond energies. Pauling noted that a heteronuclear bond is stronger than the geometric mean of the corresponding homonuclear bonds, and he attributed the extra stability to ionic character arising from electronegativity differences. The scale runs from about 0.7 for caesium and francium to 3.98 for fluorine, the reference maximum. The values are dimensionless and relative. The scale is used to estimate bond polarity.
Going deeper: Pauling Scale
Key ideas: Pauling defined electronegativity from bond energies: the extra stabilization of a polar bond A-B is delta = D(A-B) - sqrt(D(A-A) x D(B-B)), and the difference chi_A - chi_B in magnitude = 0.102 x sqrt(delta in kJ per mol). Fluorine is fixed at 4.0 as reference, the scale is relative and dimensionless.
Common mistakes and connections: Students compare values from different scales (Pauling, Mulliken, Allred-Rochow) directly. Also Pauling values are not constant for one element, as they vary with oxidation state and hybridization (sp carbon is more electronegative than sp3). It underlies the polarity predictions and partial charges.
Visualization of Pauling Scale
On the Pauling scale cesium is lowest at 0.79 and fluorine highest at 3.98, so differences predict polar versus ionic bonding. The interactive lesson shows this as a live animation or chart.
Worked example and use case
A difference in Pauling electronegativity above about 1.7 is generally taken to indicate a predominantly ionic bond.
Frequently asked questions about Pauling Scale
What is Pauling Scale?
A relative electronegativity scale based on bond energies, with fluorine at 3.98.
Is Pauling Scale a beginner, intermediate or advanced topic?
Pauling Scale is a intermediate topic in Atomic Structure & Periodicity. It builds on the vocabulary of beginner topics in this area.
What should I learn before Pauling Scale?
Study these earlier topics in Atomic Structure & Periodicity first: Anomalies in Ionization Energy, Electron Affinity, Electronegativity.
What comes after Pauling Scale?
The next topics in Atomic Structure & Periodicity are Mulliken Electronegativity and Metallic Character.
Can I practise Pauling Scale with quizzes?
Yes. The interactive lesson includes a self-check question on Pauling Scale, and the Atomic Structure & Periodicity quiz draws on every topic in this area.
Where Pauling Scale fits in Atomic Structure & Periodicity
Pauling Scale is topic 91 of 115 in Atomic Structure & Periodicity.