Question

Total number of electrons present in \( (\pi^*) \) molecular orbitals of \( \text{O}_2 \), \( \text{O}_2^+ \), and \( \text{O}_2^- \) is __________ .

Answer 1

Correct Answer: 6

To determine the total count of electrons within the \( (\pi^*) \) molecular orbitals for \( \text{O}_2 \), \( \text{O}_2^+ \), and \( \text{O}_2^- \), we must first establish the electronic configurations of these species. For \( \text{O}_2 \), the configuration is \((\sigma_{2s})^2(\sigma^*_{2s})^2(\sigma_{2p_z})^2(\pi_{2p_x})^2(\pi_{2p_y})^2(\pi^*_{2p_x})^1(\pi^*_{2p_y})^1\), yielding 2 electrons in the \( \pi^* \) orbitals. \( \text{O}_2^+ \), formed by removing one electron, has the configuration \((\sigma_{2s})^2(\sigma^*_{2s})^2(\sigma_{2p_z})^2(\pi_{2p_x})^2(\pi_{2p_y})^2(\pi^*_{2p_x})^1(\pi^*_{2p_y})^0\), containing 1 electron in the \( \pi^* \) orbitals. \( \text{O}_2^- \), with an added electron, presents the configuration \((\sigma_{2s})^2(\sigma^*_{2s})^2(\sigma_{2p_z})^2(\pi_{2p_x})^2(\pi_{2p_y})^2(\pi^*_{2p_x})^2(\pi^*_{2p_y})^1\), resulting in 3 electrons in the \( \pi^* \) orbitals. Summing the \( \pi^* \) electrons across all three species: \(2+1+3=6\). The aggregate count of \( \pi^* \) electrons is 6, which falls within the specified range.