Use the MO model to explain the bonding in BeH. When con- structing the MO energy-level diagram, assume that the Be's 1 s electrons are not involved in bond formation.

First, find the valence electron configuration of each atom involved in the bonding. - For Beryllium (Be), the atomic number is 4. Its electron configuration is 1s²2s². Since we are assuming that 1s electrons are not involved in bond formation, only the 2s² electrons of Be will participate in the formation of molecular orbitals. - For Hydrogen (H), the atomic number is 1. Its electron configuration is 1s¹. The 1s¹ electron will participate in bonding.

Now, create the MO energy-level diagram by combining the orbitals of Be and H to form new molecular orbitals. Only 2s orbitals of Be (2s²) and 1s orbitals of H (1s¹) will be involved in constructing the MO diagram. - Combine Be's 2s orbital (2s²) with H's 1s orbital (1s¹) to form a bonding (σ) and an antibonding (σ*) molecular orbital. - The bonding molecular orbital (σ) is lower in energy and results from constructive interference between the wavefunctions of the involved orbitals. - The antibonding molecular orbital (σ*) is higher in energy and results from destructive interference between the wavefunctions of the involved orbitals.

Now, fill the molecular orbitals formed in Step 2 with the total available electrons following the Aufbau principle, Pauli exclusion principle, and Hund's rule. Since we have 3 electrons in total, two electrons from Be's 2s² and one electron from H's 1s¹, these would fill the orbitals as follows: 1. Fill the lower energy bonding σ orbital with 2 electrons (one from Be and one from H). 2. One remaining electron (from Be) will be placed in the antibonding σ* orbital. In the MO model for BeH, there is one electron in an antibonding orbital (σ*), and two electrons in the bonding orbital (σ). The net bonding character will be calculated by subtracting the number of antibonding electrons from bonding ones: Net bonding character = (Bonding electrons) - (Antibonding electrons) = 2 - 1 = 1 Since the net bonding character is +1, the BeH molecule has a net bonding character, indicating a bond between Be and H atoms. In summary, by following these steps, the MO model has been used to explain the bonding in BeH, with the construction of an MO energy-level diagram and determination of the net bonding character. The BeH molecule forms a bond between Be and H atoms.