Final answer:
Directional covalent bonds have localized electron density, while non-directional covalent bonds have delocalized electron density.
Step-by-step explanation:
Covalent bonds can be categorized as either directional or non-directional based on the electron density distribution between the atoms.
A directional covalent bond occurs when the shared electron pair is localized between the two atoms involved in the bond. This means that the electrons are concentrated in a particular region, resulting in a specific orientation of the bond.
In contrast, a non-directional covalent bond occurs when the shared electron pair is delocalized and evenly distributed over a larger region. This means that there is no specific orientation to the bond.