Beginner Topic 136 of 1102 Bonding & Molecular Structure
Bond Polarity
Unequal sharing of electrons due to electronegativity difference creates partial charges.
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In-depth explanation of Bond Polarity
Unequal sharing of a bonding electron pair produces partial charges, written delta plus and delta minus, along the bond. The greater the electronegativity difference between the atoms, the more polar the bond becomes. The bond dipole is a vector that points from the positive end toward the negative end. A bond between identical atoms is nonpolar, because the electron pair is shared equally. Bond polarity influences reactivity, intermolecular forces and the acidity of many compounds.
Going deeper: Bond Polarity
Key ideas: Quantify it with the electronegativity difference from the Pauling scale: H-Cl is 0.96, C-H is 0.35, O-H is 1.24, Na-Cl is 2.1. The partial charge sits on the more electronegative atom, the arrow of the dipole points to it, and the crossed end marks the positive side. Polarity affects acidity, since a more polar H-X bond tends to give a stronger acid, though bond strength matters too.
Common mistakes and connections: A frequent slip is drawing the dipole arrow in the wrong direction, or calling a bond with partial charges ionic. Bond polarity is not the same as molecular polarity, which also needs shape. Also the C-H bond is classed as essentially nonpolar. Connects to dipole moment, electronegativity, inductive effects and ionic character.
Visualization of Bond Polarity
The difference in Pauling electronegativity grows from 0 for Cl-Cl to over 2 for Na-Cl, moving the bond from pure covalent to polar covalent to ionic. The interactive lesson shows this as a live animation or chart.
Worked example and use case
In HCl the chlorine atom carries a partial charge of about -0.18 of an electron charge.
Frequently asked questions about Bond Polarity
What is Bond Polarity?
Unequal sharing of electrons due to electronegativity difference creates partial charges.
Is Bond Polarity a beginner, intermediate or advanced topic?
Bond Polarity is a beginner topic in Bonding & Molecular Structure. It needs no earlier chemistry lessons and is a good starting point.
What should I learn before Bond Polarity?
Study these earlier topics in Bonding & Molecular Structure first: Bond Length, Bond Energy, Bond Order.
What comes after Bond Polarity?
The next topics in Bonding & Molecular Structure are Dipole Moment and Polar and Nonpolar Molecules.
Can I practise Bond Polarity with quizzes?
Yes. The interactive lesson includes a self-check question on Bond Polarity, and the Bonding & Molecular Structure quiz draws on every topic in this area.
Where Bond Polarity fits in Bonding & Molecular Structure
Bond Polarity is topic 21 of 104 in Bonding & Molecular Structure.