How do single, double, and triple covalent bonds differ?

Single, double, and triple covalent bonds differ in the number of shared electron pairs between two atoms.

In a covalent bond, atoms share electrons to achieve a stable electron configuration. The number of shared electron pairs determines whether the bond is single, double, or triple. A single covalent bond involves one shared pair of electrons, meaning two electrons are shared in total. This is the simplest type of covalent bond and is often found in molecules like hydrogen (H2), where two hydrogen atoms share a pair of electrons to achieve stability.

A double covalent bond involves two shared pairs of electrons, meaning four electrons are shared in total. This type of bond is found in molecules like oxygen (O2), where each oxygen atom shares two pairs of electrons with the other. Double bonds are stronger and shorter than single bonds because they involve more shared electrons.

A triple covalent bond involves three shared pairs of electrons, meaning six electrons are shared in total. This type of bond is found in molecules like nitrogen (N2), where each nitrogen atom shares three pairs of electrons with the other. Triple bonds are the strongest and shortest of the three types because they involve the most shared electrons.

The type of bond formed depends on the specific elements involved and their electron configurations. Elements strive to fill their outermost electron shell, and will form the number of bonds necessary to achieve this. For example, nitrogen has five electrons in its outer shell and needs three more to be full, so it often forms triple bonds. Oxygen has six electrons in its outer shell and needs two more to be full, so it often forms double bonds. Hydrogen only has one electron in its outer shell and needs one more to be full, so it often forms single bonds.