Final answer:
A covalent bond is the sharing of electrons between atoms with an electronegativity difference below 1.7, leading to either nonpolar or polar covalent bonds.
Step-by-step explanation:
A covalent bond is characterized by the sharing of electrons between atoms. When the electronegativity difference between the atoms is below 1.7, it is generally considered a covalent bond. This can be further classified into two types:
- A nonpolar covalent bond occurs when electrons are shared equally between two atoms, usually corresponding to an electronegativity difference that is less than 1.9.
- A polar covalent bond occurs when one atom has a greater attraction for the electrons than the other, often resulting from an electronegativity difference ranging from 0.4 to 1.7.
Therefore, it is the sharing of electrons between atoms with an electronegativity difference below 1.7 that describes a covalent bond, whether polar or nonpolar in nature.