2.2.5—Bond polarity

A bond is polar when a difference in electronegativity gives unequal sharing of the bonding electrons. The more electronegative atom carries partial negative character.

Compare electronegativities, assign partial charges, and draw the bond-dipole arrow toward the more electronegative atom.

For H–Cl, chlorine is more electronegative, so label Hδ⁺–Clδ⁻ and point the dipole arrow toward Cl. Electronegativity difference predicts unequal sharing within that bond; it does not by itself decide the polarity of the whole molecule.

Representative question

[Maximum number: 2]

Describe the nature of the bond between oxygen and phosphorus. Use sections 9 and 17 of the data booklet.

$\text { " } 3.4-2.2=1.2,(3.4+2.2) / 2=2.8 \text { " }$

Electronegativity difference is 1.2 .

AND

Average electronegativity is 2.8

polar covalent

Retrieve the covalent pathway: shared pairs and bond order lead to geometry, polarity and molecular polarity; structure determines network properties, IMF behaviour and chromatography; HL representations extend to resonance, formal charge, sigma/pi bonds and hybridization.

Check the representation first, then count domains, apply geometry, identify polarity or forces, and connect the structure to the requested property or HL bonding description.

2.2.5—Bond polarity

Bond Polarity

Deducing Bond Dipoles

Assessment in practice

The Covalent Model Summary

Question 1