| A | B |
|---|
| Nucleus | Center of the atom, contains protons and neutrons |
| Proton | Positively charged particle in the nucleus |
| Electron | Negatively charged particle in the electron cloud |
| Neutron | Has no charge and is in the nucleus |
| Atomic Number | The number for the element that equals the number of protons in the atom of that element |
| Mass Number | The sum of the protons and neutrons in the nucleus of an atom |
| Isotopes | atoms of a given element that have differnt number of neutrons and a different mass number |
| Energy Levels | the possible energies that an electron in an atom can have |
| Electron Cloud | a visual model of the most likely locations for the electrons in an atom |
| Electron Configuration | the arrangement of electrons in the orbitals of an atom |
| Ground State | a state in which all the electrons in an atom have the lowest possible energies |
