Atoms Quiz
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Created by:
madforshopping on October 7, 2010
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17 terms
Terms | Definitions |
|---|---|
 Democritus | -440 B.C - Greek Philosopher - atom cannot be divided -atom, small, hard, made up of single material, always moving |
| Aristotle | -384 B.C.E -Greek Philosopher - Thinks it can be divided forever |
| Dalton | 1800's - Chemist - Proposed Atomic Theory 1. Everything is made of atoms, the smallest particles that can't be divided 2. Each element has different atoms - You can mix atoms to make a new substance |
| J.J Thomson | -1897 -used the cathode ray tube to discover electrons - plum pudding model -discovered electrons |
| Ernest Rutherford | - 1911 -gold foil experiment - discovered protons -discovered the nucleus - atoms are made of empty space |
| Neil Bohr | - 1913 stated that electrons traveled around the nucleus in electron clouds - An atom can move into a different path, but it cant be in between the levels |
| Erwin Schrodinger, Werner Heisenberg | - 1900's - did more studies of electrons in the atom - found out that electrons are found in electron clouds, not paths. |
| Electron | Negatively charged subatomic particle |
| Proton | positively charged subatomic particle |
| Neutron | is a subatomic particle with no charge |
| Nucleus | - central region of an atom ( protons and neutrons) |
| Electron Cloud | - regions where electrons tend to gather - around the nucleus |
| Atomic Mass Unit | -tells you the mass of the atom |
| Atomic Number | - tells you how many protons and electrons are in the atom |
| Isotope | -atoms of the same element that have different numbers of neutrons -protons and neutrons differ in numbers |
| Mass Number | The sum of the number of the protons and the Neutrons |
| Do you need the same number of Protons and Neutrons in an atom? | No. |
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