The C2 molecule can be represented by an MO diagram similar to that in Figure 8.22a. (b) To increase the bond order of C2, should you add or remove an electron?

Verified step by step guidance

1. Understand the concept of Molecular Orbital (MO) theory, which explains the electronic structure of molecules using quantum mechanics. MO theory combines atomic orbitals (AO) to form molecular orbitals, which can be bonding or antibonding.
2. Recall that bond order in MO theory is calculated as (number of electrons in bonding orbitals - number of electrons in antibonding orbitals) / 2. A higher bond order indicates a stronger, more stable bond.
3. Examine the MO diagram for the C2 molecule, noting the filling of the molecular orbitals with electrons. Pay attention to the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO).
4. Determine the effect of adding an electron to the molecule. Adding an electron to an antibonding orbital would decrease the bond order, while adding it to a bonding orbital would increase the bond order.
5. Decide whether to add or remove an electron based on the desired increase in bond order. Since adding an electron to a bonding orbital (if available) increases the bond order, assess if the LUMO is a bonding orbital. If not, consider removing an electron from the highest antibonding orbital to increase the bond order.

Key Concepts

Molecular Orbital Theory

Molecular Orbital (MO) Theory describes how atomic orbitals combine to form molecular orbitals, which can be occupied by electrons. In this theory, electrons are delocalized over the entire molecule, and the stability of a molecule can be assessed by the arrangement of these electrons in bonding and antibonding orbitals.

Bond Order

Bond order is a measure of the number of chemical bonds between a pair of atoms. It is calculated as the difference between the number of electrons in bonding orbitals and the number in antibonding orbitals, divided by two. A higher bond order indicates a stronger bond and greater stability of the molecule.

Electron Configuration in MOs

The electron configuration in molecular orbitals determines the stability and properties of a molecule. For C2, the filling of molecular orbitals follows the Aufbau principle, where electrons fill the lowest energy orbitals first. Adding an electron to a bonding orbital increases bond order, while removing one from a bonding orbital decreases it.