Final answer:
Covalent bonds have characteristic bond lengths and are stronger when more electrons are shared between atoms, with single, double, and triple covalent bonds indicating the number of shared electron pairs.
Step-by-step explanation:
These covalent bonds have a characteristic bond length and become stronger and more rigid when two electrons are shared in a(n) single covalent bond. When atoms share four electrons, as seen in a double covalent bond, the bond is even stronger. In covalent bonds, atoms share electrons in their outermost valence shell to fill the valence shells of both atoms, ultimately stabilizing them. This sharing can vary in covalent bonds, from a single pair in a single bond, like in hydrogen gas (H-H), to two pairs in a double bond, or even three pairs in a triple covalent bond.