The molecules \(\mathrm{N}_{2}\) and \(\mathrm{CO}\) are isoelectronic but their properties are quite different. Although as a first approximation we often use the same MO diagram for both, suggest how the \(\mathrm{MOs}\) in \(\mathrm{N}_{2}\) and \(\mathrm{CO}\) might be different.

Molecular Orbital (MO) Theory is a method for determining molecular structure and properties by utilizing the wave functions of individual atoms to describe the behaviour of electrons in molecules. It explains how atomic orbitals combine to form molecular orbitals, which can hold a specific number of electrons and, thus, determine the bond order, bond strength, and magnetic properties of the molecule.

\(\mathrm{N}_{2}\) and \(\mathrm{CO}\) are isoelectronic molecules, which means they have an equal number of electrons. The total number of electrons in \(\mathrm{N}_{2}\) is 14 (7 from each nitrogen atom), while in \(\mathrm{CO}\), there are 6 electrons from carbon and 8 electrons from oxygen, also totaling 14 electrons.

To compare the MOs of \(\mathrm{N}_{2}\) and \(\mathrm{CO}\), we need to create MO diagrams for both molecules. We know that both molecules have 14 electrons, which fill the MOs in the following order: \(\sigma_{1s}\), \(\sigma_{1s}^*\), \(\sigma_{2s}\), \(\sigma_{2s}^*\), \(\sigma_{2p}\), \(\pi_{2p}\), \(\pi_{2p}^*\), and \(\sigma_{2p}^*\). Note that due to electronegativity differences between elements, the MO diagrams may not be identical between the two.

In the MO diagrams of both \(\mathrm{N}_{2}\) and \(\mathrm{CO}\), the shapes and energy levels of the molecular orbitals are influenced by the electronegativity of the atoms. Nitrogen atoms have similar electronegativity values resulting in a symmetric MO diagram, while the stronger electronegativity of oxygen in \(\mathrm{CO}\) can lead to energy levels of the MO orbitals being less symmetric. For example, in \(\mathrm{CO}\), the \(\sigma_{2p}\) orbital might be more stabilized (lower in energy) than in \(\mathrm{N}_{2}\) because of the greater involvement of more electronegative oxygen's \(2p\) orbital.

Despite having the same number of electrons, the molecular orbitals of \(\mathrm{N}_{2}\) and \(\mathrm{CO}\) are influenced by the electronegativity differences between their constituent atoms. This affects their bond strength, bond length, and bond order. In \(\mathrm{N}_{2}\), the bond order is 3 (the molecule has a triple bond) and it is quite stable due to its entirely symmetric MO diagram. In \(\mathrm{CO}\), the bond order is also 3 (triple bond), but it has a polar bond due to the difference in electronegativity between the carbon and oxygen atoms. The polarity of \(\mathrm{CO}\) also results in a more stable \(\sigma_{2p}\) orbital compared to that in \(\mathrm{N}_{2}\). This leads to different reactivity and properties of the two molecules, despite their isoelectronic nature.