In: Chemistry
Explain why bond polarity and molecule polarity are two separate characteristics.
When two atoms with different in electronegativity form bond, the more electronegative atom pull electron density of the bond towards itself and polarity developed in the chemical bond of those two atoms.
A molecule with polar bonds can be polar or nonpolar depends on the geometry of the molecule. For a molecule with polar bonds having symmetry elements in the structure is nonpolar. A molecule with polar bonds having no symmetry structures is polar.
This can be explained by the following example-
In trans structure, there are symmetry elements like the center of symmetry (i) so it is a polar molecule. the polarity of one C-Cl bond is minimized by the polarity of another C-Cl bond.