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Chemistry Unit Rev.
Stack #113625
| Science Terms | Definition |
|---|---|
| John Dalton | Atoms were spherical in shape |
| Ernest Rutherford | atoms were mostly space |
| Democritus | First person to define an atom |
| Neils Bohr | Atom has a nucleus with electrons orbitting it |
| Protons | postively charged particle in nucleus |
| Neutrons | neutral charge, in nucleus |
| Electron | negatively charged particle, orbits nucleus |
| Isotope | atom with more or less neutrons than normal |
| Ion | an atom with a postive or negative charge |
| Charge | When an atom is positive or negative due to loss or gain of electrons |
| # of protons | equals atomic number |
| # of neutrons | equals atomic mass - atomic number |
| # of electrons | equals number of protons |
| valence electrons | electrons in outermost shell |
| Valence shell | outer shell where bonding takes place |
| diatomic molecule | when 2 atoms of the same atom combine |
| physical change | change that affects size, shape, or state of matter |
| chemical change | creates a new substancen |
| Acid | substance that produces positive hydrogen H+ ions |
| Base | negative ions (usually OH-) in a solution |
| Neutral Substance | Produces Salt and water, pH of 7 |