| A | B |
|---|
| atom | the basic unit of matter |
| proton | a positively charged particle inside the nucleus of an atom |
| electron | a negatively charged particle orbiting around the nucleus of an atom |
| neuron | an atom with no charge of an atom |
| John Dalton | believed that atoms were solids with parts inside them |
| Democritus | believed everything was made of atoms, and they could not be broken down any further |
| Earnest Rutherford | believed atoms had a nucleus and electrons |
| Neils Bohr | Believed electrons orbit around the nucleus in a circular motion in levels, jumping from level to level |
| atomic number | tells how many protons an element has |
| Periodic Table of Element | where all known elements are listed in order according to families and atomic numbers |
| water | h2o |
| carbon dioxide | co2 |
| metals and nonmetals | the way the periodic table is divided |
| chemical reaction | occurs when two different chemicals are mixed together |
| compound | two or more different atoms joined together |
| neutron | a particle inside the nucleus of an atom with no charge |
| Einsteinium | an element named after Albert Einstein |
| Curium | An element named after Marie Curie |
