NATIONAL OPEN UNIVERSITY OF NIGERIA
14–16 AHMADU BELLO WAY, VICTORIA ISLAND LAGOS SCHOOL OF SCIENCE AND TECHNOLOGY OCTOBER/NOVEMBER 2014 EXAMINATION
COURSE TITLE: ATOMIC AND MOLECULAR STRUCTURE AND SYMMETRY
COURSE CODE: CHM 307
INSTRUCTION: ANSWER 1 AND ANY OTHER FOUR QUESTIONS TIME: 2½ Hours
1a) What is bond order ?
1b) State the relationship between bond order, bond length and bond strength.
1c) What information can be obtained from bond order.
1d) The ground state electron configuration of N2, with even valence electrons is
2 2 4 2
1σg 1σu 1πu 2σg .
- a) Calculate the bond orde
- b) Is N2 diamagnetic or paramagnetic.
- c) Predict the stability of the molecule and give reas
2a) List the hybrid orbitals
2b) Give the shapes and two examples each of these hybrid orbitals.
2c) State Hund’s Rule.
2d) State Pauli’s Exclusion Principle
3a) Give the full meaning of the following acronyms;
- i) HOMO
- ii) LUMO
3b) Give explanation on the differences in energies of the HOMO and LUMO.
3c) Highlight the steps to writing Resonance.
4a) Highlight the shortcomings of Aufbau Principle.
4b) Choose any three of the symmetry elements that any molecule can possess and explain in details.
4c) Explain explicitly the quantum numbers by which electron in an atom is described.
5a) Explain Pseudo-noble gas configuration and give appropriate examples.
5b) List the various molecular orbitals that can be formed from the combination of orbitals on two atoms.
5c) Discuss two consequences from Molecular Orbital theory.
6a) Highlight the steps to writing resonance, and show resonance in Ozone and
6b) Discuss Nuclear Coupling.
6c) State the usefulness of Quatum Mechanics.
7a) Account for the formation of vibration-rotation spectra.
7b) Discuss coordinates in Vibration Spectroscopy