Question

In terms of electronegativity, why is a `"C"="O"` bond in `"CO"_2` more polar than the `"F"-"F"` bond in `"F"_2`?

Answer 1

See explanation.

Explanation:

The electronegativity difference `(Delta"EN")` between two bonded atoms determines the bond character. A `Delta"EN"` `<=0.4` is a nonpolar covalent bond. A `Delta"EN"` `>0.4<1.7` is considered a polar covalent bond. A `Delta"EN"` `>=2.0` is ionic. `Delta"EN"` `>1.6<2.0` is polar covalent if a nonmetal is bonded to another nonmetal, and ionic if a metal is bonded to a nonmetal.

The `"EN"` of carbon is 2.55. The `"EN"` of oxygen is 3.04. The `Delta"EN"` `= 3.04-2.55=0.49`, which means the C=O bond is mostly nonpolar with a slight polar character.

The `"EN"` of fluorine is 3.98. The `Delta"EN"` of the F-F bond is `3.98-3.98=0`. The F-F bond is completely nonpolar covalent.

Refer to the following website for an electronegativity chart.
https://en.wikipedia.org/wiki/Electronegativity