Across
- 4. Russian chemist who organized the first widely recognized periodic table
- 9. Row of radioactive elements below the main table
- 10. Modern periodic table is organized by this
- 11. Rare earth metals usually shown in a separate row below the main table
- 12. Shell – Outermost region of an atom, important for chemical properties
Down
- 1. Element 118, the heaviest confirmed element on the periodic table
- 2. arranged elements in order of this
- 3. The rows of the periodic table
- 5. Group 18 elements that are inert due to full outer electron shells
- 6. Metals – Elements in the center of the periodic table, often used in industry
- 7. Organization that updates and confirms elements on the periodic table
- 8. The repeating pattern of chemical properties that Mendeleev observed