What is the bond order a measure of?

Bond order is a concept that quantifies the strength and stability of a bond between two atoms in a molecule. It is defined as the number of chemical bonds between a pair of atoms; for example, a single bond has a bond order of 1, a double bond has a bond order of 2, and a triple bond has a bond order of 3. The higher the bond order, the greater the number of shared electron pairs, which generally correlates with increased bond strength.

As bond order increases, the bond becomes shorter and stronger due to the greater number of electrons being shared between the bonded atoms. Therefore, it directly relates to the overall bond strength between two atoms. This is why the correct interpretation of bond order as a measure of "overall bond strength" between two atoms aligns with its definition and principles in molecular chemistry.

Other choices do not accurately reflect what bond order measures. Overall bond length and overall energy of a molecule are influenced by bond order but are not direct measures of it. Similarly, overall molecular mass does not relate to the concept of bond order.