Electronegativity Calculator

The Pauling scale is based on bond dissociation energies and sets hydrogen at 2.20. The Mulliken scale uses (IE + EA)/2 in eV. They are related by the empirical equation EN_Pauling = 0.359 x EN_Mulliken + 0.744. While the numerical values differ, both scales produce the same relative ordering of elements and the same predictions of bond polarity.

Noble gases have complete valence shells and generally do not form chemical bonds under normal conditions. Since electronegativity describes electron-attracting tendency in a bond, it is undefined for atoms that do not bond. However, Pauling values have been estimated for Xe (2.6) and Kr (3.0) based on their known compounds like XeF2.

The electronegativity difference is the primary criterion. Differences less than 0.4 produce nonpolar covalent bonds, 0.4-1.7 produce polar covalent bonds, and greater than 1.7 generally produce ionic bonds. However, this is a continuum, not sharp boundaries. The metal/nonmetal character of the atoms also matters: bonds between two nonmetals are typically covalent regardless of EN difference.

Electronegativity differences create bond dipoles (partial charges). The overall molecular polarity depends on both the bond dipoles and molecular geometry. In CO2, equal but opposite C=O dipoles cancel (linear geometry), making it nonpolar. In H2O, the O-H dipoles do not cancel (bent geometry), making it polar. Thus electronegativity alone does not determine molecular polarity.

Yes. Electronegativity increases with positive oxidation state because the effective nuclear charge on the remaining electrons increases. For example, Fe3+ is more electronegative than Fe2+. This is captured in the Sanderson electronegativity equalization principle: when atoms bond, their electronegativities equalize through partial charge transfer.