Terms : Hide Images
| 16301720726 | Nucleus | The dense positively charged mass located in the center of an atom made of protons and neutrons. |  | 0 |
| 16301720727 | Proton | A subatomic particle that has a positive charge and that is found in the nucleus of an atom |  | 1 |
| 16301720728 | Electron | A subatomic particle that has a negative charge, is found outside the nucleus and has almost no mass |  | 2 |
| 16301720729 | Neutron | A subatomic particle that has no charge and that is found in the nucleus of an atom. | | 3 |
| 16301720730 | Atomic number | A unique number for each element determined by the number of protons in an atom of that element. |  | 4 |
| 16301720731 | Mass number | The sum of the number of protons and neutrons in the nucleus of an atom. |  | 5 |
| 16301720732 | Isotopes | Atoms of a given element that have different numbers of neutrons and different mass numbers. |  | 6 |
| 16301720733 | Energy levels | The possible energies that electrons in an atom can have. |  | 7 |
| 16301720734 | Electron cloud | A visual model of the most likely locations for the electrons in an atom. |  | 8 |
| 16301720735 | Orbital | A region of space around the nucleus where an electron is likely to be found. |  | 9 |
| 16301740977 | Ion | An atom or group of atoms that has a positive or negative charge. |  | 10 |
| 16301840043 | Bohr Model | model of an atom that shows electrons in circular orbits around the nucleus |  | 11 |
