Electronegativity Chart
Compare Pauling values and classify bond polarity. This guide explains what the topic is used for, the chemistry ideas behind it, and how students should approach related problems manually.
What the Pauling Scale Measures
Electronegativity is an atom's relative pull on shared bonding electrons, scaled by Linus Pauling from about 0.7 for cesium, the least electronegative common element, up to 3.98 for fluorine, the most electronegative element. The scale has no units; it is a comparative ranking, not a measured physical quantity like mass or radius.
Noble gases are usually left off electronegativity tables entirely because they rarely form the covalent bonds the scale was built to describe.
Trends Across Periods and Groups
Electronegativity increases left to right across a period, because effective nuclear charge increases while shielding stays roughly constant, pulling bonding electrons closer. It decreases down a group, because added electron shells put valence electrons farther from the nucleus despite the larger nuclear charge.
Fluorine, oxygen, nitrogen, and chlorine sit at the high end of the scale, which is why bonds involving them are frequently the polar or acidic sites students are asked to identify in a structure.
Classifying Bond Polarity from the Difference
Subtract the smaller electronegativity value from the larger one for the two bonded atoms. A difference below about 0.4 is treated as nonpolar covalent, a difference from about 0.4 to 1.7 is polar covalent, and a difference above about 1.7 is usually classified as ionic. These cutoffs are teaching approximations, not sharp physical boundaries, so borderline cases exist.
Carbon-hydrogen bonds, despite looking asymmetric on paper, fall close to the nonpolar end because carbon and hydrogen have similar electronegativity values, which is why C-H bonds are treated as effectively nonpolar in most organic chemistry reasoning.
Exceptions to Keep in Mind
Electronegativity does not track perfectly with atomic radius or ionization energy trends in every case; transition metals in particular show much smaller and less regular electronegativity differences across a period than main-group elements do.
When classifying a bond, always compare the two specific atoms actually bonded rather than assuming a whole molecule is polar or nonpolar based on one bond in it; a molecule can contain both polar and nonpolar bonds at once.
Related Chemistry Tools
Molecular Weight Calculator
Calculate molar mass from formulas with parentheses and bracket groups.
Chemical Equation Balancer
Balance chemical equations and verify atom counts on both sides.
pH Calculator
Calculate pH, pOH, [H+], and [OH-] for acid-base problems.
Electronegativity Chart is an educational chemistry tool for compare pauling values and classify bond polarity.
It uses standard textbook equations and atomic masses. For laboratory or clinical decisions, verify with official protocols.
Yes. The lower-right chemistry chat can explain concepts and recommend relevant Chemistry Tools pages using the site knowledge base.
Yes. The tool layout collapses to one column with mobile-safe inputs.