| A | B |
|---|
| Atomic Mass | Sum of the protons and neutrons in the nucleus. |
| Atomic Number | Equals the number of protons. |
| Electron Cloud | The most likely position of an electron in an atom. |
| Electron Configuration | The arrangement of electrons in the orbitals of atoms. |
| Electron | A negative particle with little mass outside the nucleus. |
| Energy Levels | The possible energies that electrons in an atom can have. |
| Isotopes | Elements with the same number of protons but not neutrons |
| Neutron | A neutral particle with measureable mass in the nucleus. |
| Orbital | A region of space around the nucleus where the electron is likely to be found. |
| Proton | A positive particle with measureable mass in the nucleus. |
