What is the difference between single, double, and triple covalent bonds? How many shared electrons are in each?

The single covalent bond is represented by a single ' - ' and it has 2 shared electrons from the the bonding atoms.

Double covalent bond is denoted with '=' and it has 4 shared electrons

Triple covalent bond is denoted by ' _=' and it has 6 shared electrons

Explanation:

In single covalent bond each participating atom contributes one electron each to be equally shared between them in order to form a single covalent bond. Thus a single covalent bond is formed when atoms share 2 electrons together

The double covalent bond is formed when each participating atom contributes two electrons each to be equally shared between them in order to form a double covalent bond. Thus a double covalent bond results from the sharing of 4 electrons together by two atoms. For example the formation of oxygen gas molecule

In triple covalent bonds, 6 electrons are shared and each pair of electrons forms a bond which results in triple covalent bonds. Each atom contributes 3 electrons for equal sharing.

Answer

A * single covalent bond * is formed by sharing one pair of valence electrons. They are less reactive comparatviely and have a high bond length

A * double covalent bond * is formed by sharing two pairs of valence electrons. They are moderately reactive and have moderate bond length.

A * triple covalent bond * is formed by sharing three pairs of valence electrons. They are highly reactive and have a low bond length.