Here's why:
* Polar covalent bonds occur when electrons are shared unequally, creating a partial positive and partial negative charge on the atoms involved. This happens when one atom is more electronegative than the other, meaning it has a stronger pull on the shared electrons.
* Nonpolar covalent bonds happen when the electronegativity difference between the two atoms is very small or nonexistent. This means the electrons are shared equally, and there is no significant charge difference across the bond.
Examples of nonpolar covalent bonds include:
* H-H (hydrogen gas)
* Cl-Cl (chlorine gas)
* O=O (oxygen gas)
