In ion-exchange chromatography, the trade-off between this quantity and reaction kinetics arises after this quantity exceeds three. Molecules for which this quantity varies based on a binding partner’s molecular size are denoted “flexi-.” Different values for this quantity determine whether molecules follow the delta vs. lambda or fac vs. mer configuration schemes. This quantity equals two for each of the three donors in octahedral molecules during the Bailar and Ray–Dutt twists. Unlike a similar quantity, this quantity does not consider whether bound atoms are contiguous with each other. This quantity, which must be at least two for a metal to be chelated, is equal to six for EDTA. For 10 points, name this quantity that is equal to the number of atoms a ligand can donate to a metal atom and that is often contrasted with hapticity. ■END■
| 2025 ACF Nationals | 04/19/2025 | Y | 24 | 92% | 0% | 67% | 122.45 |
| Player | Team | Opponent | Buzz Position | Value |
|---|---|---|---|---|
| Andrew Wang | Illinois A | UC Berkeley A | 51 | -5 |
| Adam Fine | Chicago A | WUSTL A | 55 | -5 |
| Tony Chen | Toronto A | Waterloo A | 55 | -5 |
| Bryan Ugaz | Arizona State | Ottawa | 57 | -5 |
| Amogh Kulkarni | Georgia State | British Columbia | 59 | -5 |
| Anurag Sodhi | MIT | Chicago B | 61 | -5 |
| Richard Niu | Cornell A | Georgia Tech | 61 | 10 |
| Caleb Ott | Waterloo B | NYU | 64 | -5 |
| Allan Lee | Stanford | North Carolina A | 70 | -5 |
| Geoffrey Wu | Columbia A | Northwestern | 84 | -5 |
| Teigue Kelly | Penn State | Florida | 87 | -5 |
| Jason Zhang | Toronto C | Texas | 87 | 10 |
| Joy An | Harvard | Johns Hopkins | 98 | -5 |
| Shiva Tegulla | UCF | Winona State | 101 | 10 |
| Alex Akridge | Indiana | Rutgers | 106 | 10 |
| Nikhil Chellam | Northwestern | Columbia A | 107 | 10 |
| Conor Thompson | Iowa State | Minnesota | 107 | 10 |
| Raymond Chen | Toronto B | Virginia Tech | 107 | 10 |
| June Yin | WUSTL B | Yale | 110 | -5 |
| Joseph Chambers | Virginia | Illinois B | 110 | -5 |
| Calvin Bostleman | Ohio State | Vanderbilt | 110 | 10 |
| Derek Chen | Columbia B | RIT | 113 | -5 |
| Yashwanth Bajji | Michigan | Cornell B | 113 | -5 |
| Tiffany Zhou | Florida | Penn State | 129 | 10 |
| Albert Yingzhi Nyang | LSE | UC Berkeley B | 129 | -5 |
| Isaac Mammel | Maryland | North Carolina B | 135 | 10 |
| Colin Veevers | Ottawa | Arizona State | 137 | 10 |
| Russell Nip | British Columbia | Georgia State | 137 | 10 |
| Ezra Santos | Chicago B | MIT | 137 | 0 |
| Neal Joshi | WUSTL A | Chicago A | 137 | 10 |
| Alan Xie | Yale | WUSTL B | 137 | 10 |
| Ryan Rosenberg | NYU | Waterloo B | 137 | 10 |
| Cade Reinberger | RIT | Columbia B | 137 | 10 |
| Rohan Shelke | UC Berkeley A | Illinois A | 137 | 10 |
| Shardul Parthasarathy | Illinois B | Virginia | 137 | 10 |
| Maximilian Niebur | Johns Hopkins | Harvard | 137 | 10 |
| Rasheeq Azad | North Carolina A | Stanford | 137 | 10 |
| Liam Kusalik | Waterloo A | Toronto A | 137 | 10 |
| Anuttam Ramji | UC Berkeley B | LSE | 137 | 10 |