According to molecular orbital theory, what is the bond order of the Ne_2^{2+} ion?

• A. 0.5
• B. 1
• C. 2
• D. 0

Answer: (B)

Verified step by step guidance

1. Identify the total number of electrons in the neutral Ne_2 molecule. Each neon atom has 10 electrons, so Ne_2 has 20 electrons in total.
2. Since the ion is Ne_2^{2+}, remove 2 electrons from the total count, resulting in 18 electrons to place in molecular orbitals.
3. Write the molecular orbital electron configuration for Ne_2^{2+} using the molecular orbital energy ordering for homonuclear diatomic molecules in the second period: \(\sigma_{2s}\), \(\sigma_{2s}^*\), \(\sigma_{2p_z}\), \(\pi_{2p_x} = \pi_{2p_y}\), \(\pi_{2p_x}^* = \pi_{2p_y}^*\), \(\sigma_{2p_z}^*\).
4. Fill the molecular orbitals with 18 electrons according to the Aufbau principle and Pauli exclusion principle, pairing electrons in lower energy orbitals first.
5. Calculate the bond order using the formula: \(\text{Bond order} = \frac{(\text{number of bonding electrons}) - (\text{number of antibonding electrons})}{2}\). Count the electrons in bonding and antibonding orbitals from your configuration and apply this formula.