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| 4205895041 | John Dalton's atomic theory | 1. All matter is made up of atoms (T) 2. Atoms of a given element are identical in size and mass (F- isotopes) 3. Atoms can't be subdivided, created, or destroyed (F- protons, neutrons, and electrons) 4. Atoms combine in single whole-number ratios (T) 5. Atoms are combined, rearranged, or separated to form compounds (T) | 0 | |
| 4205847184 | Henry Becquerel (1896) | Accomplishment: observed radioactive decay of U Significance: atoms are not unchangeable | 1 | |
| 4205849652 | J. J. Thompson (1897) | Accomplishment: discovered electrons by experimenting with the Cathode Ray Tube Significance: atoms are not indivisible | 2 | |
| 4205900363 | Goldstein (1886) | While experimenting with Cathode Ray tube, he discovered the presence of protons | 3 | |
| 4205851420 | Max Plank (1900) | Accomplishment: studied blackbody radiation Significance: proposed the quantinization of energy | 4 | |
| 4205852786 | Albert Einstein (1905) | Accomplishment: examined light-metal interaction Significance: photoelectric effect: light behaves like particles | 5 | |
| 4205854493 | Ernest Rutherford (1908; 1911) | Accomplishment: studied radioactive emissions; used alpha radiation to bombard Au (gold) Significance: named alpha, beta, and gamma radiation; discovered nucleus | 6 | |
| 4205856762 | Robert Milikan (1908) | Accomplishment: measured electron charge Significance: determined an electron's mass (1/2000 of mass of a proton) | 7 | |
| 4205862170 | Henry Moseley (1913) | Accomplishment: studied x-ray spectra of atoms Significance: defined atomic number | 8 | |
| 4205863309 | Neils Bohr (1913) | Accomplishment: investigated atomic spectra Significance: proposed quantized levels | 9 | |
| 4205865571 | Louis deBroglie (1924) | Accomplishment: theoretician Significance: proposed matter exhibits wave-like behavior | 10 | |
| 4205868125 | Werner Heisenberg (1927) | Accomplishment: did theoretical work Significance: developed Uncertainty principle | 11 | |
| 4205869572 | Erwin Schrodinger (1926) | Accomplishment: did calculations on the H atom Significance: developed the wave equation | 12 | |
| 4205871078 | James Chadwick (1932) | Accomplishment: studied nucleus Significance: discovered the neutron | 13 | |
| 4205876311 | atomic number | the number of protons in the nucleus | 14 | |
| 4205876322 | atomic mass | the total number of protons and neutrons | 15 | |
| 4205884137 | isotopes | elements with the same atomic number but different atomic masses (different number of neutrons) | 16 | |
| 4205892912 | average atomic weight of an element | (exact weight of isotope #1)(abundance of isotope #1) + (exact weight of isotope #2)(abundance of isotope #2) | 17 | |
| 4205888021 | mass spectrometry | technique in which gaseous atoms are bombarded with high energy electrons which removes one or more electrons from an atom to form positive ions that can be separated according to their masses when subjected to a magnetic field | 18 | |
| 4205910800 | Relationship between speed of light, wavelength, and frequency | c = λv (c- 2.998*10^8 m/s; λ- wavelength; v- frequency) | 19 | |
| 4205913122 | Relationship between energy of photon and frequency | E = hv (E- energy of photon; h- Plank's constant (6.636*10^-34 Js); v- frequency) | 20 | |
| 4205918767 | Coulomb's Law | calculates the force between two particles F = q1q2/r^2 F- force between two particles; q1, q2- charges; r- distance separating them | 21 | |
| 4205925695 | n | principal quantum number which indicates distance from nucleus; possible values: 1, 2, 3... | 22 | |
| 4205927233 | l | orbital quantum number which indicates sublevel (s, p, d, f); possible values: 0, 1, 2... (n-1) | 23 | |
| 4205928843 | m1 | magnetic quantum number which indicates orbital orientation; possible values: 0, ±1, ±2...(±l) | 24 | |
| 4205932305 | ms | spin quantum number which indicates whether the spin is clockwise or anti-clockwise; possible values: ±1/2 | 25 | |
| 4205934078 | Aufbau principle |  | 26 | |
| 4205943401 | Effective nuclear charge (Zeff) | the actual charge an electron feels because of the nuclear charge cancelation by electrons in the same principle energy level (cancels fraction of charge) and core electrons (cancels full nuclear charge) Zeff = Z - S (Z- atomic number; S- number of shielding electrons) | 27 | |
| 4205947141 | Shielding effect | describes balance between the pull of protons and the repulsion from core electrons | 28 | |
| 4205951489 | Atomic Radius | the distance between the nuclei of adjacent atoms in an element Trend: INCREASES DOWN the periodic table (PT) because of the increase in principal energy levels and DECREASES ACROSS (left to right) because the electrons in the same principal energy level are attracted to nuclei with greater Zeff | 29 | |
| 4205956010 | Ionization Energy | the energy required to pull one electron away from a gaseous atom Trend: DECREASES DOWN the PT because of increasing number of energy levels and the greater shielding effect and INCREASES ACROSS because of the increase in attractions to more highly charged nuclei Exceptions: Group 13 (B, Al, Ga, Zn, Tl) because the outermost electron occupies the p sublevel Group 16 (O, S, Se, Te, Po) fourth electron in p sublevel is paired | 30 | |
| 4205961259 | Electron Affinity | the energy released when a gaseous atom gains an electron to form a negative ion Trend: DECREASES DOWN the PT because of the attraction between the nucleus and the added electrons becomes smaller with the increasing distance between the electrons and the nucleus and INCREASES ACROSS the PT Exceptions: Al, Si, P, S, Cl have higher electron affinities than those above them because of the greater electron repulsion present in the smaller atoms | 31 |
