Screenshot the PhET molecules for the following, and add the element symbols to the VSEPR skeletal structures:
1. Use molecular orbital theory to explain the differences between the bond energies and bond lengths of F₂.and F₂.
6. The compounds Br2 and ICI have the same number of electrons, yet Br2 melts at -7.2 C, whereas IC melts at 27.2° C. Give an explanation as to why this is expected.
8. The dipole moment of HF is 1.92 D. Given that the bond length is 91.7 pm, calculate the separated charge q, assuming the point charge model.
9. How many normal modes of vibration are in the following molecules:
10. List the following molecules in order of increasing dipole moment: H₂O, CBr4, H₂S, HF, NH3, CO₂. Explain your answers.
The rotational constant of 12C16O2 is 0.39021 cm. Calculate the C=0 bond length.
For the Lennard-Jones potential discussed in class, show that the potential has a minimumat r min = 21/“0 with a minimum energy equal to —e.
13. What is the dominant intermolecular interaction in the gas phase between a) NH3 and HCl, b) N₂ and O2, c) H₂O and CH3COOH? Explain each answer.
2. Consider an N₂ molecule in its first excited electronic state, that is, when an electron in the highest occupied molecular orbital is promoted to the lowest unoccupied molecular orbital. (a) Identify the molecular orbitals involved and sketch a diagram for the transition. (b) Compare the bond order and bond length of N₂ with N₂, where the asterisk denotes the excited molecule. (c) Is N₂ diamagnetic or paramagnetic? (d) When N₂ loses its excess energy and converts to the ground state, it emits a photon of wavelength 470 nm, which makes up part of the auroras lights. Calculate the energy difference in kJ/mol between these levels.