Question
Didymium (“dye-DIM-ee-uhm”) safety glass lenses contain two of these elements, praseodymium (“praise-ee-oh-DIM-ee-uhm”) and neodymium (“neo-DIM-ee-uhm”). For 10 points each:
[10m] Identify this group of elements with a partially-filled 4f orbital, which are nicknamed for being difficult to separate rather than their individual scarcity.
ANSWER: lanthanides [or lanthanoids; accept rare-earths or rare-earth elements or rare-earth metals]
[10h] Four separate elements, including three lanthanides, are named for being discovered in this Swedish village. Though they aren’t named for it, gadolinium, holmium, thulium, and scandium were also discovered in this village.
ANSWER: Ytterby
[10e] One of the four elements named for Ytterby, erbium, is used to dope glass for optical amplifiers for these devices. A red beam of collimated light is produced by these devices through stimulated emission.
ANSWER: lasers
<Chemistry>
Summary
| 2024 ACF Fall at Cornell | fall | Y | 9 | 20.00 | 100% | 78% | 22% |
| 2024 ACF Fall at Ohio State | fall | Y | 8 | 21.25 | 88% | 100% | 25% |
| 2024 ACF Fall at Georgia | fall | Y | 13 | 20.77 | 92% | 92% | 23% |
| 2024 ACF Fall at North Carolina | fall | Y | 9 | 17.78 | 100% | 56% | 22% |
| 2024 ACF Fall at Claremont Colleges | fall | Y | 5 | 26.00 | 100% | 100% | 60% |
| 2024 ACF Fall at Illinois | fall | Y | 9 | 23.33 | 100% | 89% | 44% |
Data
| CWRU A (UG) | Miami C (DII) | 10 | 10 | 10 | 30 |
| Michigan D (UG) | CWRU B (DII) | 10 | 0 | 10 | 20 |
| Miami B (UG) | Michigan State A | 10 | 10 | 10 | 30 |
| Michigan State B | Michigan C | 10 | 0 | 10 | 20 |
| Miami A (UG) | Ohio State A (UG) | 10 | 0 | 10 | 20 |
| Michigan A (UG) | Ohio State C (DII) | 10 | 0 | 10 | 20 |
| Jefferson County Scholars (DII) | West Virginia A (UG) | 10 | 0 | 10 | 20 |
| West Virginia B (UG) | Michigan B (UG) | 10 | 0 | 0 | 10 |