Packet 5: Bonus 11
Answer the following about the orbital structure of methane, for 10 points each.
[10e] Linus Pauling proposed a theory of this phenomenon to explain why methane has four identical orbitals. Orbitals denoted sp2 and sp3 have undergone this process of mixing to form bonds.
ANSWER: orbital hybridization [accept hybrid orbitals or hybridized orbitals]
[10m] Methane spectra generated by this technique instead show one orbital and a triply degenerate state. The readout of an “angle-resolved” form of this technique is a function of dipole selection rules and the spectral function.
ANSWER: photoelectron spectroscopy [or photoemission spectroscopy or PES; accept X-ray photoelectron spectroscopy or XPS or angle-resolved photoelectron spectroscopy or ARPES; prompt on spectroscopy]
[10h] Landis and Weinhold used a theory described by this adjective to argue that all of methane’s orbitals are identical. This adjective describes bonding orbitals with maximized electron density, as well as sets of hybrid orbitals that are intermediates between atomic and molecular orbitals.
ANSWER: natural [or natural bond orbitals or NBOs or natural hybrid orbitals or NHOs]
<Indiana, Chemistry> | E. Prelims 5 - Indiana + Vanderbilt + MIT
| Heard | PPB | E % | M % | H % |
|---|---|---|---|---|
| 21 | 12.38 | 100% | 24% | 0% |
Conversion
| Team | Opponent | Part 1 | Part 2 | Part 3 | Total | Parts |
|---|---|---|---|---|---|---|
| British Columbia | Rutgers | 10 | 10 | 0 | 20 | EM |
| Cambridge | North Carolina | 10 | 0 | 0 | 10 | E |
| Chicago A | Georgetown | 10 | 0 | 0 | 10 | E |
| Cornell | NYU B | 10 | 0 | 0 | 10 | E |
| Georgia Tech A | Ohio State | 10 | 0 | 0 | 10 | E |
| Georgia Tech C | Toronto B | 10 | 0 | 0 | 10 | E |
| Harvard | Texas | 10 | 0 | 0 | 10 | E |
| Illinois A | NYU A | 10 | 0 | 0 | 10 | E |
| Johns Hopkins | UC Berkeley B | 10 | 10 | 0 | 20 | EM |
| Maryland B | Georgia Tech B | 10 | 0 | 0 | 10 | E |
| Michigan | Illinois B | 10 | 0 | 0 | 10 | E |
| Northwestern A | Bruin | 10 | 0 | 0 | 10 | E |
| Penn State | Purdue | 10 | 0 | 0 | 10 | E |
| Pittsburgh | Columbia B | 10 | 0 | 0 | 10 | E |
| Stanford A | Chicago B | 10 | 0 | 0 | 10 | E |
| Stanford B | Brown | 10 | 0 | 0 | 10 | E |
| Toronto A | Minnesota | 10 | 10 | 0 | 20 | EM |
| UC Berkeley A | UCF | 10 | 10 | 0 | 20 | EM |
| UCLA | Virginia Tech | 10 | 10 | 0 | 20 | EM |
| Virginia | Columbia A | 10 | 0 | 0 | 10 | E |
| Waterloo | Maryland A | 10 | 0 | 0 | 10 | E |
Summary
| Tournament | Edition | Match | Heard | PPB | E % | M % | H % |
|---|---|---|---|---|---|---|---|
| Main Site | 2026-04-17 | ✓ | 21 | 12.38 | 100% | 24% | 0% |