A The CN^? ion has a total of 10 valence electrons: 4 from C, 5 from N, and 1 for the ?1 charge. Placing these electrons in an energy-level diagram like Figure 6 "Molecular Orbital Energy-Level Diagram for a Heteronuclear Diatomic Molecule AB, Where ?" fills the five lowest-energy orbitals, as shown here:

Because ?_N > ?_C, the atomic orbitals of N (on the right) are lower in energy than those of C. B The resulting valence electron configuration gives a predicted bond order of (8 ? 2) ÷ 2 = 3, indicating that the CN^? ion has a triple bond, analogous to that in N₂.