Question
In Rutherford spectroscopy, modeling this effect with a potential that decays as (read slowly) “one over r, times e to the minus r” prevents the cross-section from diverging. Adding this effect to a helium atom’s Hamiltonian reduces the variational parameter from 2 to “27 over 16.” This effect is estimated by: adding multiples of 0.3, 0.35, 0.85, or 1 at quantum numbers n and n minus 1, then subtracting the sum from atomic number to give (*) “Z-effective,” when using Slater’s rules. This effect and orbital penetration explain why ionization energy decreases down a group. The lanthanide contraction occurs because 4f electrons do not participate in this effect. For 10 points, name this effect in which core electrons block the nucleus’s tug on valence electrons. ■END■
Summary
2023 PACE NSC | 06/10/2023 | Y | 34 | 91% | 9% | 0% | 101.39 |
Buzzes
Player | Team | Opponent | Buzz Position | Value |
---|---|---|---|---|
Charles Heydt | Midtown | Walter Payton | 53 | 20 |
Joseph Chen | Richard Montgomery | Plymouth | 54 | 0 |
Tanay Bodducherla | Mira Loma | Woodland | 54 | 0 |
Ibrahim Mohammad | Chattahoochee A | Thomas Jefferson C | 58 | 20 |
Alex Xu | Canyon Crest | Thomas Jefferson B | 62 | 20 |
Ali Hamzeh | Kinkaid | Belmont | 70 | 0 |
Kaushik Gollamudi | Barrington B | Lincoln-Way East | 77 | 0 |
Keith Delarosa | Hoover B | Detroit Catholic Central B | 78 | 0 |
Aeres Zhou | Detroit Country Day | Rockford Auburn A | 78 | 10 |
Rohan Dalal | Johns Creek B | Thomas Jefferson D | 78 | 0 |
Vincent Wang | Irvington A | Mexico | 80 | 10 |
Matthew Kohn | Hunter A | University Lab | 80 | 10 |
Russell Dillak | Northmont B | Maggie Walker B | 81 | 10 |
Rohan Kher | Barrington A | Thomas Jefferson A | 83 | 10 |
Omar Hamid | Dunbar | Maggie Walker A | 88 | 10 |
Braden Booth | Dallas County | Detroit Catholic Central A | 91 | 10 |
Bernie Jin | Winston Churchill B | Hinsdale Central | 91 | 10 |
Joy An | Choate Rosemary Hall | Northmont A | 91 | 10 |
Krish Chinta | Innovation Academy A | Chattahoochee B | 93 | 10 |
Brayden Ferrell | Heights | Parkway West | 101 | 10 |
Aryan Pathak | Lake Highland | Moberly | 104 | 0 |
Alexa Rosenberg | Hunter B | West Point | 104 | 10 |
Armaan Ahmed | Mercer County | Waukee | 104 | 10 |
Alvin Guo | Winston Churchill A | William Fremd | 117 | 10 |
David Bertolasi | Belvidere | Norris | 117 | 10 |
Jeffrey Xu | Johns Creek A | Troy | 117 | 10 |
Arnou Thammarak | New Brighton | Carl Sandburg | 118 | 10 |
Grace Sun | Stevenson B | Norman | 120 | 10 |
Jay Lee | Carbondale | Stevenson A | 121 | 10 |
Varun Venkatagiri | Innovation Academy B | John Adams B | 121 | 10 |
Sam Macchi | Belmont | Kinkaid | 121 | 10 |
Nolan King | Elkhorn North | Saint Joseph | 121 | 10 |
Sarah Dong | Solon | St. Mark's | 122 | 10 |
Brielle Rach | Rockford Auburn B | John Adams A | 122 | 10 |
Sanjay Ranjith | Thomas Jefferson D | Johns Creek B | 122 | 10 |
Anthony Chalhoub | Detroit Catholic Central B | Hoover B | 122 | 10 |
Aneesh Swaminathan | Plymouth | Richard Montgomery | 122 | 10 |
Chris Goolsby | Detroit Catholic Central C | Washington | 122 | 10 |