. 1. Cathode ray tube experiment is the experiment that led to the discovery of the nucleus. 2. Atom is the smallest particle of a substance that is capable of independent existence. 3. Dmitry Mendeleev arranged elements in the periodic table according to atomic masses. 4 Manganese belongs to the VIIB group. 5.Iron and selenium are ionic compounds. 6.Isotopes are atoms that have the same atomic number but differ in atomic mass. 7. Moscovium has an atomic number of 115. 8. An unknown element is given the atomic number of 115 and proton of 115. 9. The horizontal rows that determine a repeating pattern are called group or family. 10. Electrons have a negative charge and equal the number of neutrons.
