| A | B |
|---|
| nucleus | center of an atom |
| electrons | charged particles that spin around the nucleus |
| protons | positively charged particles in an atom |
| protons and neutrons | found in the nucleus |
| neutrons | uncharged particles found in the atom |
| Molecules | two or more atoms joined together |
| chemical bonds | strong attraction between two bonds |
| instruments used to study atoms | electron microscopes, atom smasher, and X-rays |
| atom | smallest part of an element |
| John Dalton | first to study atoms. |
| Modern atoms | electron cloud |
| Earlier atoms | thought to be solid |
