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ChemCh4Ch25
| Question | Answer |
|---|---|
| Democritus | 450 BC; "atomos" -Greek for indiisible, matter consists of elementary solid sphere particles |
| John Dalton | 1803; Atomic theory- elements made of atoms, which are indivisible particles, atoms of same element are identical |
| JJ Thompson | 1897; electrons were like plums embedded in a positively charged "pudding" this it was called PLUM PUDDING MODEL; found the electron |
| Rutherford | 1911; from the Gold Foil experiment; atom is mostly empty; small dense, positive nucleus @ center; alpha particles are deflected if they get close enough; electrons in empty space; NUCLEAR MODEL |
| Bohr | 1913; electrons found ONLY in specific orbits around the nucleus; PLANETARY MODEL |
| Schrodinger | 1926; mathematically described the behavior of electrons in atoms; locations based on probability; QUANTAM MECHANICAL MODEL |
| James Chadwick | 1932; using alpha particles discovered a meutral atomic particle with a mass close to a proton: neutron |
| Protons and neutrons are ___ fundamental particles | NOT |
| In a neutral atom, the number of _______ = the number of _________. | protons, electrons |
| If there is not an equal number of protons and electrons it is an ___. | ion |
| Do all atoms of an element have the same masses? | no |
| isotope | atom of the same element that differs in the number of neutrons |
| atomic mass | average of all the natural isotopes of that element |
| Z= ______ _____ | atomic number |
| A= ____ ______ | mas number |
| Radioactivity | process by which nuclei emit particles and rays |
| radiation | the penetrating rays emitted by a radioactive source |
| alpha particles | helium nucleus (+2 charge, large mass) |
| beta particles | high speed electron |
| gamma rays | high energy light (photon) |
| Nuclear decay | need stable ratio of neutrons to protons; neutron-to-proton ratio determines type of decay that occurs |
| transmutation | conversion of an atom of one element to an atom of another element |
| Alpha emission | 4:2 He |
| Beta emision | increases # protons, decreases # neutrons, mass # same atomic # +1 |
| Positron emission | proton->neutron, mass # same atomic # -1 |
| electron capture | proton-> neutron, mass # same, atomic # -1 electron captured |
| Two types of nuclear energy | fission and fusion |
| fission | splitting a nucleus into two or more smaller nuclei by neutorn bombardment |
| fusion | combining of two nuclei to form one nucleus larger mass |
Created by:
AlanaR
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