Question

How can you determine the bond polarity between two atoms?

Answer 1

In order to determine the bond polarity between two atoms, their respective electronegativities must be determined. Electronegativity is the tendency of a bonded atom to attract bonded electrons to itself. The difference in electronegativity, `Delta"EN"`, can help predict the bond type.

In general, a `Delta"EN"` of < 0.4 indicates a nonpolar bond, while a `Delta"EN"` of 0.4 - 1.7 indicates a polar covalent bond, and a `Delta"EN"` > 1.7 indicates an ionic bond. https://www.chem.wisc.edu/deptfiles/genchem/sstutorial/Text7/Tx71/tx71.html

The `Delta"EN"` for the C-Cl bond = `"|2.55 - 3.16| = |0.61|"`. (`Delta"EN"` is an absolute value; it is never negative.) A `Delta"EN"` of 0.61 indicates that the C-Cl bond is polar covalent.