Pick any two elements and see the electronegativity difference (ΔEN), dipole arrow direction, δ+/δ− partial charge labels, and automatic nonpolar/polar/ionic bond classification.
Bond polarity is the single most useful predictive tool in introductory chemistry — from it alone you can predict molecular polarity, intermolecular force type, boiling point trends, and solubility behavior, which is why AP Chemistry Unit 2 treats electronegativity difference as a starting point for so many other topics.
Electronegativity, on the Pauling scale, measures an atom's tendency to attract shared electrons in a covalent bond. The electronegativity difference (ΔEN) between two bonded atoms determines bond character along a continuum: ΔEN below about 0.4 is considered nonpolar covalent (electrons shared essentially equally, as in a C-H bond, ΔEN ≈ 0.4), ΔEN between 0.4 and 1.7 is polar covalent (electrons shared unequally, creating partial charges), and ΔEN above 1.7 is considered ionic (electron transfer rather than sharing, as in NaCl, ΔEN ≈ 2.1).
In a polar covalent bond, the more electronegative atom pulls electron density toward itself, acquiring a partial negative charge (δ-), while the less electronegative atom is left with a partial positive charge (δ+). The dipole arrow convention points from δ+ toward δ-, representing the direction of unequal electron sharing — and correctly drawing this arrow is a prerequisite for later predicting overall molecular polarity from bond geometry.
A critical distinction that trips up many students: bond polarity and molecular polarity are not the same thing. CO2 contains two highly polar C=O bonds, but the molecule itself is nonpolar overall because its linear geometry causes the two bond dipoles to point in exactly opposite directions and cancel. Predicting molecular polarity correctly requires combining bond polarity (from electronegativity) with molecular geometry (from VSEPR) — neither alone is sufficient.
This bond polarity visualizer lets you select any two elements, instantly calculates ΔEN and classifies the bond as nonpolar, polar, or ionic, and displays the dipole arrow with δ+/δ- labeling — building the electronegativity intuition that later molecular-polarity and intermolecular-force topics depend on.