| A | B |
|---|
| protons | positive electric charged particle in center of atom |
| neutrons | neutral charged particle in nucleus of atom |
| electrons | negative charged particle moving rapidly in shells surrounding nucleus of atom |
| nucleus | center area of the atom containing protons & neutrons |
| Element | all atoms have the same # protons |
| atomic number | number of protons in the nucleus of an atom |
| identifies the element | number of protons |
| protons + neutrons | atomic mass of the element |
| Compound | two or more elements chemically combined, form new substance |
| atom | smallest part of an element |
| molecule | smallest part of a compound |
