This unit test covers atoms, atomic structure, mass number, atomic number, and isotopes. Additionally, questions cover the history of atoms, subatomic particles, and models of atomic structure. Students determine the number of protons, neutrons, and electrons in atoms, ions, and isotopes. See complete list of topics below. The 50 Questions include fill in the blank, multiple choice and calculations of average atomic mass. Both printable and digital versions of this resource are included. The