Electronegativity difference (ΔEN) is one of the fastest ways to predict how a bond between two atoms will behave — whether electrons are shared evenly, shared unevenly, or transferred outright. This calculator looks up Pauling-scale values for two elements, computes ΔEN, and classifies the resulting bond so you can check homework, sanity-check a Lewis structure, or refresh your memory on a specific pair of elements.

How the Electronegativity Calculator works

Enter each element as a symbol (H, O, Cl, Na, and so on) and the calculator looks up its Pauling-scale electronegativity from a standard reference table. If you already know the value you want to use — for a different scale, or a value from your textbook that differs slightly from this table — you can type a decimal number directly into either field instead of a symbol, and it will be used as-is.

ΔEN is simply the absolute difference between the two resolved values: |EN₁ − EN₂|. The calculator then classifies the bond using the standard general-chemistry cutoffs (nonpolar below 0.5, polar covalent from 0.5 to 1.7, ionic above 1.7) and estimates percent ionic character with Pauling's exponential approximation, (1 − e^(−ΔEN²⁄4)) × 100.

Inputs and what they mean

Each input accepts either an element symbol or a direct electronegativity value. Symbols are case-insensitive ("cl", "Cl", and "CL" all resolve to chlorine). Direct values are useful when you need to check a hypothetical ΔEN, or when your course uses a slightly different electronegativity table than the one built into this calculator.

Noble gases (helium, neon, argon, krypton, xenon, radon) have no universally agreed Pauling electronegativity value, since they rarely form conventional bonds — entering one of their symbols will not resolve to a value unless you type a number directly.

Limits and edge cases

The 0.5 and 1.7 thresholds are teaching conventions, not sharp physical cutoffs — a ΔEN of 0.49 and a ΔEN of 0.51 describe bonds that are, in reality, nearly identical in character. Percent ionic character from Pauling's formula is likewise an estimate; it does not account for atomic size, bond length, or the geometry of the molecule, all of which affect real ionic character. For rigorous bonding analysis (e.g. molecular orbital calculations), electronegativity difference is a useful first-pass heuristic, not a substitute for quantum-chemical methods.