Which of the following terms refers to the strongest bond involving shared electrons?

The term that refers to the strongest bond involving shared electrons is a covalent bond. In a covalent bond, atoms achieve stability by sharing pairs of electrons, allowing them to fill their outer electron shells. This sharing can occur between two nonmetals and can involve single, double, or even triple bonds, depending on the number of shared electron pairs.

Covalent bonds are characterized by their strength due to the direct interaction between the positively charged nuclei of the bonded atoms and the negatively charged shared electrons. This results in a strong electrostatic attraction that holds the atoms together effectively, making covalent bonds among the strongest types of chemical bonds.

In contrast, an ionic bond, while strong in another sense, involves the transfer of electrons from one atom to another, creating charged ions that attract each other. Metallic bonds involve a 'sea of electrons' shared among a lattice of metal cations, which is a different bonding mechanism. Polar bonds are a type of covalent bond where electrons are not shared equally, resulting in a molecular dipole, but they do not imply greater bond strength than a non-polar covalent bond. Thus, covalent bonds are recognized for their strong and stable nature through electron sharing.